One of the kits are ddmtuning.com. It has lifetime warranty however the warranty process takes very long. My other kit was purchased in 06 & is still running strong, believe it or not it was the cheap xentec kits on ebay after a week one of the bulbs started to flicker during initial start up so I emailed the seller & they sent me a brand new pair of bulbs no questions asked & i didn't have to send in the old bulbs. So if you just want to try it out I would recommend xentec. Mainly for the quick returns in warranty.