This is where I will chime in. Not usually checking general section but the post caught my eye. Let me free of some questions about the claims of that seller.
Leds do produce heat, they can produce a lot of heat depending on how many and how much voltage they are running. I sell blue leds for $0.40, each shipping included. They warranty on mine and 99% of the manufacters is 100,000 hrs or 14yrs. which ever comes first. trust me, i don't think anyone has ever bothered claiming warranty on any of them.
With the prices he has listed thats $6.24 each with shipping. My LEDs can be seen
here. And i have a wide range of them, if you buy them in 50-100 packs they are much cheapers. as little as $0.25 each for blue. which would mean for their cost of aprox 75+ LEDs, which is way better. Most of my tutorials for the contour are down but I promise I will be getting the recent ones down. I have some led work and shipments to do along with some other stuff for cegers and I have taken on more then I can bite at one time.
here is a good place to start for what leds will look like, in several different stock and custom locations.
http://www.iwired.us/gallery/thumbnails.php?album=7 you can also find some on my car domain web site at
http://www.cardomain.com/memberpage/641474/4 and here
http://www.cardomain.com/memberpage/641474/5 . and a few more of the ones Plato spoke of, they are sold from
www.superbrightleds.com (i hate them!)
http://iwired.us/cars/contour/99ses/ 
Search around in the aesthetics forums, you'll find all you need to know about LED's. There's actually a plug and play LED that goes in your existing under dash holes if you want that look, that the seller says costs $300.