ET35 will not need spacers as it will sit further out from the hub if you had a ET55 you would need a 10mm spacer to have the wheel sat at a ET45 offset, i run ET35 17" bolero TQS wheels and they clear S4 B6 345mm front discs, so basically the more lower the ET is then you have more Clearance/poke hence why the RS4 runs a ET29 offset iirc to sit flush with the wider arches.