Yes 355 can fit under 18" not all models of wheels. I have copy of Volks Japan Racin JR3 and they can accommodate BBK
All comes down to the alloy wheel spoke design I'd say. Some will fit, some won't as you say.
Yup. Buddy has Rotora Forget 6/4 kit on his Z and we test fitted mine wheels on his car. Manage to squeeze under 18" even without spacer
Sent from my SM-G850F using Tapatalk