I had dreems of putting 18's on my mk3 but i was told by a few garages that it can be done but may cause damage to arches even though they have been rolled. - however i am still looking for someone who can roll the arches for me, but i dont like the vibrations when going over bumps? how can you stop this>? can this be allowed if certain springs can be fixed?
ive been having the same dreams lol.
an 8x18 wheel with a 215/35 tyre i think could be done, you will defo need the arches rolled, and possibly cut at the back to get them to fit, there was a yellow mk3 in PVW a little while ago with 18's, looked uber
any decent body shop should be able to roll your arches, the rears on mine have actually been cut leaving no lip on the inside at all, which means i can totally load her up, with her already lowered 60mm, over 8.5x17 wheels with 215/40 tyres... and get only a tiny bit of rubbing when going over bumps.
basically... with a standard suspension set up, i cant see 18's causing any problems, might have to watch the offset on the vectra alloys tho.