I have 8x18 ET35 front and ET25 rear with 215/35 front tyres and 225/35 on the rear, I reckon that's the best compromise if you actually want to be able to carry passengers in the rear. Trouble is with 17" wheels no one seems to make a 225/40 rear tyre which would be ideal on the rear with a 25 offset and maybe a 215/40 front.