The cost of dealer service shop rates and parts are most likely about the same at all dealers, although I got a quote of $1800 plus labor for a replacement brake booster for my 840Ci at one dealer, $1100 including labor at the dealer I have used, and $750 (part alone) from Zymunt. So I did the replacement myself. The Service Rep can make a big difference in what you spend at a dealer. I had to replace the catalytic converters and O2 sensors on my 840. The rep said the cost at the dealer would be $3400 plus labor but he gave me the number of an after market manufacturer that said they would build an exact replacement, using my old ones as a pattern, for $350 each plus the O2 sensors. When I got there they recommended an off the shelf pair that they replaced with labor for $300. Passed smog OK so I am happy. This rep has been good to give me hints and guidance on things he recommends not be done or that I could do myself. As long as he is there I will probably patronize this dealer. Norm 1995 840Ci, 108.8K miles