My list of trusted VW shops, in no particular order.
Walnut Creek VW
Griffin Motorwerke
Karmakanix
European Auto Repair (Alameda)
Clayton Auto Repair (Tell Irfan I sent you)
I have had work done on my vehicles at all of the above shops and would not hesitate to return to any of them.
I would also consider
AVS
Tomas Sport Tune
Bus Lab (VW Bus specialists in Berkeley)
Sonnen Motors
My Fords go to
Clayton Auto Repair
East Bay Ford
Walnut Creek Ford
Midas, Big O Tires, Jiffy Lube, and Oil Changers all in Berkeley
My Ducati goes to
Nichols in Milpitas
It may go to Addiction Motors in Emeryville at some point in the future.
My Honda Sabre and my Chevy van are primarily serviced by yours truly, as are all of my vehicles when I feel like saving some money.
Justin is my preferred GTG mechanic. I also trust Pete and Matt, although neither of them have worked on my car...yet...
If you own a Honda, Toyota, or other Japanese car
Berkeley Mini Car is an outstanding shop. My mother has been using them for about thirty years.
Marty's Motors in Richmond is also very good for most any vehicle. Marty is an expert on Volvo, and very good on Toyota, Honda, even some domestics.
My trusted body shops are
Stewarts in Richmond and Bay Auto Body in Concord (Tell Todd I sent you).
Full disclosure, I am called upon to work on locks at many of the above shops, have been for years. I reciprocate with those who treat me well and do good work. I know lots of other good places, but they will be left off this list, at least for now.
I will also point out that I have had problems with work done at GTGs. Returning to have the problems addressed is not really an option. I had to choose between paying others and doing the work myself to correct those problems. I choose to do it myself and make sure it was done right.
To each his own.