@phaheem 18" wheels can fit over the M3P PUP brakes. I have 18x8.5" wheels on my 2021 M3P (with PUP), same size as the 18" aero wheels.My understanding is that you’d still have to get a relatively large wheel/tire size because of the larger brake rotors on the P than what’s on the LR. So you’d still have to pay a premium for 19”/20” wheels/tires even if you dump the OEM uberturbine wheels
It is a snug fit and some 18s don't clear due to barrel or spoke shape, but many are known to fit, there are plenty of known good options. Some, like the wheels I got, are made specifically for the M3P, with the center bore machined for the "stepped lip" and the correct offset to match stock fitment. No centering rings or spacers needed.