I have DDM in my Audi, and I DO NOT recommend them.
Caveat: Audi's are touchy cars with lots of electronic gremlins that are hard to chase down and work-around.
I have DDM's 55w kit and when it works, they're great. It's about 50/50 whether the left headlight is going to fire or not when you turn them on. I even have the code eliminators (another in-line resistor basically, to draw more amperage so the sensors will continue to supply power to the ballast and not drop that headlight). If it doesn't come on, I have to open the hood and bang on the headlight housing a few times, then close it and it'll usually work.
Personally, I'm on the hunt for a better solution myself. I've had the DDM's since January 2010 and haven't had any problems except that they don't always come on. May, or may not be directly related to the Audi however. At this point, I'm gladly going to pay $$$$ to get quality lights in there (probably OEM).