aftermarket hids
 

What brand are guys running?

FIRST you need to get the projector type housings or the factory HID housings...
I'm running ddm tuning HID's
I've also used hid extra ones with good results

Why can't I use the housing that it has

HID's on a standard housing has no cut off/focus and will blind oncoming drivers ...

This has given HIDS the bad name they have by putting hid bulbs into standard housing...

I have them in my trailblazer SS with stock housing and they are great

Great for YOU ... Not for oncoming drivers

Wow dude thanks for the welcome you need to calm down! I guess caddy Lexus VW and all the other builders could care less about it also. As very few use a projection beam

First off you come asking about HID's and what you are running I give you the info and WHAT needs done to run them properly...

Lexus and VW use specially designed housing FOR Hid's ... And far different then just popping HID bulbs in halogen housings.

All the Caddy's I've seen ARE using projectors as are BMW/Accura/Audi Ect

They are designed with bulb sheilds , and special reflectors to focus the beam and give it a cut off preventing blinding oncoming drivers.

Projectors are the best easiest way to give the beam focus and retrofit into housings.

look at retrofit source

Heres some light reading on the subject
http://aseclub.net/forums/index.php?...1#entry1294631