I love these things... they look good on the bike (in my humble opinion), help out a lot on dark roads, and make us more visible to the "cagers" during the day. However of all the projects I've done this one has the greatest number of different configurations available that I've found, and several that I haven't really looked at. For that reason I'll briefly talk about each of the options I looked at and the pros and cons for each. Note that any prices mentioned were correct at the time of writing, but may have changed since then.

Original OEM Triumph lightbar
This one's probably the easiest, because everything you need's supplied, it all fits, and all the mounting points are on the bike. If cutting wires or drilling holes in your bike makes you nervous you should probably go with this one. Pros: Well made, easy to fit, everything matches the bike, and if something goes wrong with it the people at your Triumph dealership won't make angry faces at you. Easy to buy, just rock up to your local Triumph dealer, sell your soul to them, and wait the six weeks for it to sail out from England on a boat. Unless you're in the USA some dealers might complain that it's illegal to actually USE, but that's not their problem. Cons: Like all OEM parts it's far more expensive that it's worth, and for some weird reason Triumph decided to put the light switch on the side of the left-hand light.

JC Whitney lightbar to suit Hond Shadow as fitted to a bike owned by www.bonnevilleamerica.com member "BonnyUSA"
JC Whitney (www.jcwhitney.com) market a lightbar to suit the Honda VT600 Shadow (1985 - 1999) and Shadow Deluxe (1988-1999) that will fit our bike with only minor modifications. It's part number is 01ZX1176W and you can find it using the search engine on their website. For the lights they stock 5" chrome plated off-road lights that fit and look good against the bike, part number ZX888602P. These use an easy to find and replace H3 halogen bulb. Price US$16.99 each. There is also 4.75" chrome plated light housing that better matches the shape of our lights, but is more expensive (US$21.95each, part number ZX019960N). To use these you'll also need their halogen sealed beams (US$9.95 each, part number ZX019961T for clear or ZX019962A for amber). While these do look better on our bikes, finding a replacment sealed beam to suit in the middle of nowhere is probably going to be more difficult than finding a standard automotive bulb. You'll also need some mounting brackets to fix the lights to the bar, these are part number ZX019963R and are US$4.29each. With both of these options you'll need to fashion a wiring harness and purchase a switch and relay yourself. Whitney also stocks a kit (part number ZX012006U US$149.98) with everthing you'll need, including the wiring harness, relay, switch and mounting block (which you probably will want to change anyway) and some funky chrome end-caps to seal the ends of the bar, though how you're supposed to feed the wiring through the bar and out the ends with these caps in place is beyond me.

Complete lightbar kit available from www.JCWhitney.com
Pros: A lot cheaper than the OEM bar kit (about 1/3 the price). Cons: You'll need to re-drill the mounting holes to fit our bikes, the bar is a lot narrower than the standard one which leaves the lights VERY close to the headlight (in fact some people have reported needing to fit rubber tape to to stop the lights rubbing the headlight!), and the bar's not the best made; the chrome's VERY thin and polishes off easilly, and the central mount often is often up to an inch out of centre leading to the lights having to be fitted off-centre as well to make things symetrical. Unless you want to purchase the kit (which uses the sealed beams) you'll need to D-I-Y the wiring, which also means cutting off the standard Triumph plug and soldering.
There's nothing at all to stop you having your own bar manufactured - after all it's just a piece of steel tubing with a few bends and three brackets welded on. Get the thing chromed, painted, or powder-coated to suit your tastes, find some aftermarket lights to bolt on and you're set. You could even get really creative and find some second hand Virago headlights and have both low AND high beams.

OEM Bar fitted with aftermarket lights on my bike.
This was my solution. I didn't like the Whitney bar for various reasons and wanted the wider look of the Triumph bar without the cost of their whole kit. I discovered Triumph dealers can order just the bar itself without the rest of the kit (probably for accident repairs) which I purchased, then ordered the 5" offroad lights as mentioned above. Because I'm in Australia I bought them through Autobarn. They're not a stock item but they can be ordered from a catalogue from the importer - Aussie Custom Auto Concepts of something similar. One thing I didn't realise at the time was that the bottom mounts aren't very well chromed and rusted after six months. It's probably a good idea to take just the mounts in for a decent re-chroming before you fit the lights, as it's a pain to remove them once it's all in place. I used a switch (for legal reasons) which disables the driving lights, and mounted it in the tank console in the hole intended for the alarm's LED. (When I later mounted an alarm I purchased a seperate LED mounted in a chrome bezel and mounted it in a hole drilled in the console, in the centre of the idiot lights. Looks good.)
Pros: A very "standard" look without the "standard" pricetag, and if you bend the bar your Triumph dealer can easilly order another. You'll also have much fewer problems fitting other standard accesories such as windscreens with this system. Cons: You still have to manufacture the wiring harness and get a seperate switch & relay, although the lights I bought came in a kit with a complete harness to suit a four wheel drive (SUV for the yanks) which I simply cut it to size to suit the bike.
If you've bought the original Triumph kit, nothing more than some basic tools... if you've wimped out completely and got the dealer to fit it, what're you doing reading this? What I needed to buy seperatley was a switch with a weather-proof boot, a pair of mounting bolts (stainless steel, hex-headed, M5 40mm long with matching nylock nuts and a pair of washers), a soldering iron & solder, some male and female "bullet" connectors and a crimping tool, a packet of black zip-ties, and some heat-shrink tubing. Don't use electrical tape, it comes off after a while. The wiring harness & relay came with the lights, if yours didn't you'll about 3 metres of an appropriately thick wire (at least two colours is good, black, red, and blue is better), two metres of lighter "hookup" wire for the switch, some black sleeving to make it all look neat, and a 12V relay and matching socket. A voltage meter or test light is also useful, but not essential.
Once you have collected all the parts, the first trick is making them all play nice. This will be an issue if you've used the Triumph bar with the aftermarket lights as the bar's mounting holes are too small for the light mounting bolts - simply file them out with a rat-tailed file, or drill with an appropriate sized bit. If you're using the JC Whitney light bar you'll need to redrill the bar's central mounting holes to suit the bike's mount points. The easiest way to do this would probably be by making up a carboard template of the lower triple tree's mounting holes, offer the bar up to the bike to find the best (centered) location, then using the template to mark and drill the holes in the bar. Since I didn't use the JCW bar I don't have a template, but if some nice person wants to scan theirs and email it to me I'll include it here. Once this is done, mount the bar on the bike under the lower triple tree with the bolts fed in from the top downwards. Leave the bar loosley mounted as we'll be removing it again later - this is all just to ensure mechanical fit before we get stuck into the wiring. Mount the lights on the bar, and if you're using the JCW bar get them roughly symetrical. Don't worry too much about aiming them now, as no matter how careful you are they'll be wrong - just leave them pointed in roughly the right direction. That's the easy part done.
Remove the tank console by unscrewing the three hex headed screws and unplugging the wiring harness. Remove the rear (if fitted) and front seats. Turn off the fuel tap and disconnect the fuel line. Unbolt the fuel tank mount and slide the tank back a few inches to allow you to reach under the front right of the tank and disconnect the breather hose from the base of the tank. Remove the tank completley and set it on something that will protect it's finish (a flattened carboard box is good). Locate the driving light connector and relay mounting point on the right side of the frame above the engine, as shown in the picture. The picture shows the extra relay already mounted using zip ties to attach it both to the mounting point and the next relay. If you're using the original Triumph kit you will have a rubber mount which simply slides onto the frame's mounting point.
If you're using the OEM kit, you should simply wire it up as per the instructions from this point. This kit includes the correct connector to match the bike's wiring, but is only legal in the USA, as it leaves the driving lights on at all times which is illegal in most other countries. For the rest of us who're doing it ourselves, we will need to cut the connector off (don't do it yet, we'll do it one wire at a time) and solder our new wires directly to the bike's, insulating the joint with heatshrink tubing. I'm also assuming you'll be using a disable switch, if not you can simply wire the appropriate pin to the switch terminal on the relay.
If you examine the relay you'll find it has four pins, each marked with a number. For convenience I'll refer to those pins as "switch" (pin 85), "earth" (pin 86), "supply" (pin 30), and "load" (pin 87). Remove the battery cover and disconnect the negative terminal of the battery. Offer up the sleeving to the bike to follow the original wiring harness from near the headstock of the frame to a point above the carburettors, then cut it to length. Fold the light hookup wire in half then feed it through the sleeving along with the the heavy blue and black wires, and cut them to length leaving approximatley eight inches (20cm) out either end, then cut the bend in the hookup wire to create two seperate wires. Use zip-ties to bind the new harness to the original one, leaving the ties slack to allow for later adjustments.
Wiring part 1: Removing the original connector and fitting the relay and main harness.
You now need to decide how you wish the lights to operate. They can operate at all times, only with the low beam, or only with the high beam. The last one (high beam only) is the legal preference for most countries other than the USA. The system you're using dictates the first wire we'll cut and solder. Here's the pinout for the connector:
If you want the lights on at all times use wire number 5 on the connector, for operation only with headlights on low beam use wire number 2, and for high beam use wire number 3. Locate the wire of your choice, then cut it from the connector. Solder one of your hookup wires to it and insulate the joint. Solder the second hookup wire to the "switch" terminal on the relay's socket. Cut wire number 1 from the connector, then solder a short length of heavy red wire to it and insulate, then solder the other end of it to the "supply" pin on the relay's socket. Solder the heavy blue wire to the "load" pin on the relay's socket. Cut a short length of heavy black wire and twist it onto the end of the already mounted black wire, solder both of them to the "earth" pin of the relay's socket, then cut wire number six from the connector, solder it to the short length of black wire and insulate.Cut the remaining wires from the connector, insulate the ends and use a zip-tie to bind them to the frame out of the way. Mount the relay as shown, then from the front of the bike pull the wires through the sleeve till they're snug and neat, ensuring none of them are in contact with sharp edges or hot parts. Tighten the zip-ties to hold the new harness in place against the original one. Run the two hookup wires along the sub-harness that travels to the console, and trim them to match the console's connector, and crimp on one male and one female bullet connector to the hookup wires. Zip-tie into place. Do not cut the heavy black and blue wires short at this point.
Wiring part 2: Fitting the switch.

Switch and weather-proof boot shown against a zippo lighter for scale.
Take the console and remove the rubber bung filling the hole for the Alarm LED. If you have a weather-proof boot for your switch and there are two mounting nuts on the switch, discard one of them. Adjust the mounting nut so that enough of the switche's thread shows through the console's hole that the boot's nut secures it tightly. Take two pieces of hookup wire approximatley 12" long and solder them to two of the switches terminals. (If your switch has three terminals like mine, chances are you need the centre one and one of the outside ones.) Insulate the joints, then run the wires neatly alongside the console's sub-harness, threading the, inside the console's rubber boot and cut them level with the console's connector. Crimp on a male and female bullet connector. Zip-tie in place as needed.

Tank console with switch mounted in Alarm LED's position. Note replacement LED in centre of console mounted in chrome bezel.
Wiring part 3: Wiring up the light bar.

Remove the lightbar from the bike leaving the lights in place on the bar. You will need two lengths each of heavy black and blue wires, each about twice the length of the bar. Solder (and insulate) one of the black lengths to each of the light's earth connections, and one of the blue to each of the light's positive connections. Feed the four wires into either end of the bar and out the hole in the middle Pull the wires through till they're snugly in place. Mount the bar back on the bike thenlay the wires neatly along the lower triple-tree and on the left side of the headstock to a point just under the edge of the tank's normal location, leaving enough slack to allow for the forks' normal movement. Cut to length, feed a short piece of black sleeving over them, then crimp on a male and a female bullet connector; this forms the bar's sub-harness. Cut the blue and black wires from the bike's harness to meet the bar's sub-harness and crimp on a male and female bullet connectors, ensuring that the black and blue wires have the correct polarity. (It's probably easier to join the wires coming from the bar into two pairs, then solder a short eg: 2" length to each one to attach the bullet connector, than trying to crimp two wires into each connector. Remember to insulate everything.) Do not connect the sub-harness to the harness yet.
Testing and final assembly.
Go back over EVERY connection you've cut or made, ensuring that they go where they're supposed to and that they're all insulated. Don't skimp on this as it can mean the difference between a good job and a cooked bike on the side of the road on a rainy night. Once you're satisfied that it's all as it should be, remove the relay and connect the negative terminal of the battery. With the bike switched off you should have 12 volts at the "supply" pin of the relay socket, and 0 volts on all the others. Turning the ignition on (and switching the headlight to your selected operation method, eg: low beam or high beam) should provide 12 volts at the "switch" pin of the relay socket. (Note - Operating the dip switch should not change this if you've selected the American "always on" method of operation.) If there are no problems turn the ignition off, install the relay, then turn the ignition back on. You should now find 12 volts present at one of the switches bullet connectors. If so turn the ignition off, plug in the switch then turn the ignition on again. With the switch in the "on" position you should find 12 volts at the end of the blue wire where it meets the bar's subnarness, and 0 volts there when the switch is in the "off" position. (If your switch is upside down just undo the weather-proof boot and turn the switch around.) Turn off the ignition, connect the bar's sub-harness, then turn the ignition back on. With the switch "on" the driving lights should illuminate, and if you've selected a non-American operation method they should operate with the dip switch as well.
Reassembly of the bike is the reversal of disassembly, with care taken to ensure that the breather hose is not caught or crimped below the tank, and that the fuel line is well secured and no fuel leaks are present. Aim the lights standing the bike upright in a dark place about 3 metres/10' from a vertical wall. Align each light so that it is level with the headlight (on low beam for American setups, on the appropriate beam for beam-operated setups) and just to either side of the light. It may be required to cover one light while aiming the other to avoid confusion.
Pictures and information "borrowed" from : www.bonneville.com members BonnyUSA for the picture of his lights setup and GreyBeard for the pinout of the connector, JC Whitney, Triumph UK.
All care but no responsibility taken - it worked for me but if you burn down your bike using this information it's your problem.