I have a neon kit that I bought to put under my Insight. I've had it for over a year and haven't gotten around to installing it yet. Partly because there's no good place to put it, partly because I'm just too darn busy, partly because I bought it on eBay and both of the long tubes are defective and the seller is a deadbeat. I've been thinking about doing a set of LEDs instead.
I installed Low Glow blue/purple ones on mine. I had to mod the shields so the light shines through. I u email me I'd be happy to send pictures of what it looks like. I can't figure out how to put a picture in the post.[/img]
Aluminum screws in an aluminum body would be your best bet. Although steel and most aluminum alloys are very close in the galvanic series and steel is more cathodic (more "protected"). So small steel screws in the big aluminum body would actually be trying to corrode all the aluminum, so it's not as bad as one would think.
In the converse, however...aluminum screws in a steel body...the corrosion would be "focused" on the small aluminum screws and they would have a tendency to disappear in relatively short order.
I use to have a National Winning Import Show car. So I will help you out with this. Actually, the whole underside of the car is perfect for under carriage lights. Just simple cut 2 holes in the plastic under the car and simply use a zip tie to hold the lights on(you may want to do this in 3 sections for each light, and of course you should remove the front bumper and place the front light on to the frame, so it is not noticable. I live in orlando fl and can help you out if you live here.