235/40x18 as rears?

[daver]

According to the tech specs (for Toyo T1-R's) the number of revs per km for the 235/40 is within 1% of that for a 255/35.

With 18" rims on the back of a 3-er being 8.5" wide though, I reckon that 235 would be a better fit and, lets face it, even the 330i hardly warrants 255 section rubber. A pair of 235's is also £50 cheaper which is better than a poke in the eye.

Anyone followed this thought process to reality and care to comment?

[plowy]

Stick to what the OEM fitment is mate, if it would be better on 235's BMW would have put them on there to start with and for the sake of £50 is it really worth it ?