As someone who is researching a possible M3P lease....why would you take off the wheels that you just paid for? To downsize for a more compliant ride?
@Basscadet Well I might not bother on a lease.
Our S P85 came with a similar skinny sidewall setup, 245/35R21 on 20x8.5", and it wasn't long before one of them cracked. We switched the S to 245/45R19 on 19x8.5" and no more cracked wheels.
Was the road it cracked on in terrible condition? Yes. But so are many roads, and most cars don't get cracked wheels just from driving down them. We never had a cracked wheel before or since those 21s.
The M3P 235/35R20 on 20x9" setup looks like the same recipe for cracked wheels. Not something we want to deal with again, so I ordered 18x8.5" forged wheels for it before we even picked up the car. With 245/45R18 Bridgestone Potenza Sport on them everything is better than stock - ride quality, dry grip, wet grip, power steering feel, tire pricing, and wheel protection.
I think the Uberturbines look really good on the 3, as do the 21s on the P85, but huge cast wheels with really skinny sidewalls are not very practical for us. Your experience may vary, especially if your roads are well maintained!