I will trust an occasional touchless wash (maybe 4 times total in the 2 years of ownership) when she gets really dirty and I don't have the time to hand wash. I never hand dry the car after the touchless because I don't trust that it's actually clean enough to run a towel over the paint.
I would never consider letting someone else hand wash the Z unless I know them personally and have seen their car wash habits in action. The hand wash places around here cost $50+ for the basic service and are guaranteed to swirl your paint from what I've seen. Their hand drying procedure is horrific, typically using the same small towel ($hitty, regular cotton towel - not even microfiber) for the entire car, folding it over maybe once if you're lucky
