I just got a RWD M3 last month. I bought some used 20" sport wheels (8.5" ET 35) and 255/35/20 Michelin Pilot Sport AS4. I found a thread on Reddit with someone claiming this exact tire/wheel setup did not rub....well the front tires rub for my car now 🤦♂️
I want to say there is about a 3mm...