I currently have 17's on my Avon running Sierra discs all round. code on wheel states e 38 which I assume is offset. seen a potential set off 15's with the code e 35. will these fit?

yes its only 3mm difference

Someone will correct me if I'm wrong, but I think it means they will stick out a tiny bit more that's all

as above they will stick out 3mm more

but don't worry about it - most sierra's were either ET38 or ET35 anyway
(my XR4x4 was ET35)

[Edited on 24/5/2011 by mcerd1]

They might not stick out more, most 17s are 7 inch wide, where as most 15s are 6 inch wide, so they will be 25mm narrower, 15mm of that will be lost on the inside, and 10mm would be lost on the outside.

Cheers guys I'm looking at 15 x 7's with a 35 offset in lieu of my 17 x 7's 38 offset. looking at the comments above this se ems to be OK.