Can anyone give me some advice on whether to purchase a HID Xenon Conversion Kit for my 2007 Scion Tc, or just buy the xenon bulbs, is there a difference, and also some recomendations on kits would be appreciated

 

I'd suggest to read this:
https://www.scionlife.com/forums/viewtopic.php?t=103288

This is a pretty hot topic for some people and that thread might not really answer your question, but maybe give you some ideas.

 

www.xenonpros.com