I had 8j rims with 175s on the rear of my euro look polo, no problem with the mot as the tread didnt quite stick out the wheel arch when lookin from above although tire side wall an the rim clearly did! Although it can be a very grey area with the police i know quite a few ppl from the VAG scene that have had problems with the police because of stretch an wheels outside of the arch even if the tread doesnt show. I was pulled when i had mine due 2 runnin german pressed plates, they looked over the whole car checking the tread on all tires lights etc an didnt even mention the stretch! Lol must have just been my lucky day or somethin cos they didnt even do me 4 my plates cos i had Uk ones in the boot an fitted um while they were there!