Originally Posted by timannnn

Basically you find either audi bi-xenon projectors or mercedes e55 projectors (not active xenon where light moves when you turn corners). The ones I have are audi's. The audi bolt pattern is slightly different than the factory halogen projectors but only by two holes.
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10. Now all that's left is wiring up the ballasts. On mine I mounted the philips ballast to the bottom of the headlight just like the factory. I also did the capacitor trick (it's in the w211 forum under hid sticky). The wiring is the same as installing an aftermarket "rebased" kit. For the bi xenon portion (getting the xenon high beams to work) I simply tapped into the factory high beam wiring (made it look factory too) to turn the solenoids on when hitting the high beams. It doesn't draw that much current so it will not throw any bulb error codes. At least on mine it doesn't. Now when I switch on the high beams I have the bi-xenon high beams and the factory 55 watt high beams. Let's just say "let there be light". It is extremely bright.