I'm not familiar with the kit, but since it's a kit and pre-wired then more than likely you'll just need to wire it up along with mount it.
See if I understand this correctly -- the tail lights are LED but the license plate lights are lamps (bulbs)? Smaller wire is fine with LED's as they use FAR less power than bulbs. The tail light, even if it is a bulb, doesn't use much.
LED's only flash slower/faster when used with flashers without some type of sink. The kit probably includes it, though I can't be sure. Flashers rely on the bulb to drain a capacitor to regulate the flashing. Since LED's use far less power, they drain the capacitor slower or not at all, and cause the flashers to operate erratically. The cheapest way to correct this is to place a power resistor between the positive & negative leads to the kit, but you'll have to play with the resistance to get the correct timing.
In some cases, the flashers are built into the bulb and rely on the bulb heating up to open a circuit (similar to a fuse, but they reset themselves). In this case, the LED's won't flash at all unless the kit includes the timing circuit.
The more expensive but correct method is to buy or make a timing circuit (555 timer comes to mind) and eliminate the flashers. It may be supplied with the kit or pre-installed.
LED's can burn out or fail, but it's very rare. If they do, more than likely you'll have to solder them in.
You're probably more confused now than ever.
Last edited by acinonyx; 09-25-2008 at 02:54 PM.