Hi Guys, I've owned my 2009 MK5 GTI for about a month or so now, and after 112k miles everything is pretty tip-top...besides my headlights... Like all early 2000's cars, they have started to fade pretty badly. Rather than go through with all the trouble of chemicals, hacks, and tips. I've decided to just go and buy some new headlights altogether(just the housing, not new bulbs). However, when shopping for them, most of all the listings say "NOT COMPATIBLE WITH FACTORY XENON/HID HEADLIGHTS", mine being a 2009, and judging by the light omitted, I am pretty sure I have Xenons. My question is, what is the difference, and why can't I use Halogen headlight buckets if my car has Xenons?