Personally I love an auto. When I was young I, like everyone else, wanted to be in control. That's what we said. Changing gear, double clutching on the way down would impress the girls outside the chippy. Was all part of driving
Back then some auto boxes were terrible anyway. Clunky and Maybe just 3 gears and a tiny engine which didn't have enough torque to keep going after such a big ratio change.
But then I had a mercedes 380SLC with auto and my eyes were opened. More torque than you can shake a stick at and super smooth changes. Just put your foot down and point it where you want to go and sit back and enjoy the ride letting the car do the work.
A Z3 is more of a 'sports car' than a big merc but I'm of an age where I wear my hat the right way round and just like sitting back and cruising. I don't need to stir a stick in a bucket of cogs to enjoy a drive.
So yep. I'd have a 2.8 Auto no problem.