Like what others said in the last thread, you should search up older threads first
Nor-Cal Tuning Shops
Recommended Shops in the BAY AREA
And the question is better suited for the NorCal regional forum
Northern California Region - Nissan 370Z Forum
That being said, those threads are pretty old. The only mention in those threads I can really vouch for is Z-Car garage. Literally THE place to go if you want something done right, although they get heavily booked with bigger jobs.
Nissan SF as pretty good imo. They're one of those dealers you can source Nismo and Stillen mods. Just a PITA to get to.
Nissan Burlingame was nice. Their ramp to exit sucks, though.
Otherwise, look up some Nissan-specific specialty shops. I've been to A&J in San Jose, and they're pretty good guys. Was gonna try The Garage on 10th Street in SF, but I totally lean on weekend availability and turnaround.