OEM route will require you to contact your dealer. Each Xenon headlight is about 700 dollars, plus you'll need the xenon control unit for each at about 400 dollars, plus misc parts. Low/high beam bulbs are about 200 each as well.
Aftermarket route, just search "Depo" "bavarian exclusive LS1" or "sonar" here on the forum. There have been a few people who have gone this route, and it looks great. Some earlier adopters have had issues, but others seem to have had no problems.
Here's a big thread about aftermarket options:
http://www.1addicts.com/forums/showt...highlight=depo
Here's the sale thread of the bavarian exclusive ones. i would contact the guy who started the thread since he works for bav x:
http://www.1addicts.com/forums/showt...highlight=depo
and a couple others with people who have them installed:
http://www.1addicts.com/forums/showt...highlight=depo
http://www.1addicts.com/forums/showt...highlight=depo