It began at Thunderhill Raceway Park. My car, a 2007 Audi RS4, developed a problem in the rear differential after a day of track sessions. As Griffin was on site, as they are so often, to help us club members during track events, I talked with Curly about the problem. He promptly took the car for a spin and identified the likely problem. While I wasn't able to continue at the event, Curly did suggest that I could drive the car home without further damage and then decide what to do. Now, given the noise I would have just called for a tow which would have been very costly. So I took his advice and got it home, no problem. Curly then did some research as to what the specific problem might be and I drove the car to Griffin. Unfortunately, once they got the diff out and open, the damage was severe - it couldn't be rebuilt. So a new differential was required. The Griffin team got the job done expediently and got the car back to me as soon as possible, working perfectly. Curly and several others were always responsive, helpful and a pleasure to deal with even as the news was bad. I highly recommend Griffin Motorwerke for any and all service requirements!