I've had a bunch of broken cupholders on my Z4MC if that counts. Otherwise, I haven't really had any issues with any cars I've owned *knock on wood*
When I first got my '03 Cobra it had some issues with the ignition system (I think from the dealer's detailer screwing up), and that's the closest to a reliability issue I've ever had. Even my 135i was problem free until I crashed it.
'08 Black Saphire/Black Z4 M Coupe
RIP Gretta: Blue Water/Lemon 135i. Died to save me.