When your Porsche, BMW, or Mercedes is brand new, please, go take it to the dealer to get it worked on but, once it's out of warranty, take it to United Car Care. They do excellent work for a fair price and work on all kinds of import cars. Over the past ten years they have worked on my Ferrari 308, my BMW, my specialty Beck 550, my Alfa Romeo, and my current Porsche Boxster. When you take your car to the dealer they will often charge you for 3 hours of work even though their mechanic only spent 15 minutes on the car. If you complain they will tell you that 'there is a fixed rate for that repair'. At least at United Car Care if they spend 3 hours on your car, it means they actually did 3 hours of work. Highly recommended!