USE A TELEPHONE.
Call the BMW, MB and Porsche dealership- ask the receptionist who they use for their dent work..often times they'll volunteer the name (unfortunately 50% of the time they get the name wrong!).
They may even say "Oh the guy is here Thursday afternoon" and you just cruise by on Thursday and chat him up.
The other benefit is that if they are the regular guy for the Porsche dealer, they are the regular guy for the Porsche dealer!
For a dent guy, time is money- they do not sit on-line to answer emails... they want to minimize the time wasted and keep regular routes. If you can fit into that they be more likely to help you if it doesnt take an hour to come see you AND have you wind up saying "I'll get back to you". By meeting 2 or 3 you can get a vibe, AND get an opinion on how perfect or easy the repair will be....
GL
A