i heard good things about them so you should be ok ordering from them. as far as learning about LEDS head over to HIDPLANET.com and look in the led forum or the university and that will answer alot of questions
The ones i used off Ebay were pre-wired with resistors and had long enough wires attached that i didn't need to add anything on. Was able to reach the center of the light bar as they came. Very nice surprise.
Just found the business card from the guy i bought mine from. www.plasmaled.com and the guy's email is: [email protected]
Should be able to email him and maybe get an auction set up.
Could save a couple bucks over buying them directly from a retailer.
Here are the ones that I have purchased (twice!) along with the resistors I use. Oh...and I buy them online from Mouser.
I have a total of 66 LED's in the current version. Total cost for LED's and Resistors: ~$25 shipped.
It took me a few hours to solder them all up and place them, and I'm more than happy with the results!
PM me if ya want tips and/or pics on how I did my setup!