So what is the best size for 18" 215/35/18 to minmise rubbing or something else? - and what is the offset range that fits without guard rub

I only have a lowly 16VT so brembo clearance is no issue

225/35/18 are the size for the 20 vt but not sure what sizes the 16vt had as std

225/40 is a really close fit, and alot of people have tried to fit them and had scrubbing i have had a look, and i could not fit 225/40, about 3mm too large.

get 35 on the front & 40 on the back for comfort...

In my experience of fitting big wheels to my cars I almays go with the smallest tyre available. Simply to help the fitting and to stop rubbing and it also looks better. I know by doing this that I may put the speedo out by a few mph but I think the fitting is more important. Even if the speedo is a little out you can always take this into account when you need to take a reading. You cant take into account you have bigger wheels when trying to do 3 point turns or get it through the MOT.

Im about to get a set of 18's hopefully this week and I'll be fitting 215/35 Toyos.

don't get the logic there alleystew, you should be aiming for the same rolling radius. if you get that right, then there will be no rubbing issues as both the new wheel/tyre combo will be the same as the old wheel/tyre combo.... 225/35/18 is the best available size if you are upgrading from 205/50/16, 215/35/18 is closest to the 225/45/16 radius

its the wideness of the tyre that causes the rubbing...ive got 35s on now & its a hard ride after std wheels. im getting 40s on my new alloys that are cuming on wednesday!

ive 225/40/18 and there fine no scrubing at all and its been dropped 35mm on apex springs...???

BUT meagy, if you have a good luck under your arches, where it catches/could catch on full lock is on the shoulder point/edge where side wall and tread meet so this is affected by the width as you said, AND the profile height, as if the profile height of the tyre increases so does the diameter, forcing this edge/shoulder further out. Hope that makes sense. I think it has alot to do with tyre choice and each caar, as some seem to have probs and some not. do the 16vt have the same arch liners with vents to cool oil etc????