mine are 7.5x17 and iv got 215/40/17 tyres on them. Im lowered 40 all round and theres no probs at the front. at the back though when i hav passengers in there theres a bit of a rub round corners etc. just ned to get rid of the lip inside the arch. Its been done on one side but not the other, il get round to it at some point.
its hard to say whats best as there are so many possibilities with size wheels - width and round, size tyres and if your goin to strech them on or not, and how much your lowered/goin to lower by. imo 17s do fit well on a mk3. 40mil drop gets them sat nicely under the arches. go for 7 or 7.5 for the widht to avoid needin arch work and 205/215x40 or 45 tyres. lower profile can make it look lowered more and the wheels look bigger wich is a plus!
thats not really helped has it.
