what tyres? different tyre types make a difference as well as some have squarer shoulders than others.

i had 245 35 17's on 7.5 x 17's with ET35 offset and the arches needed to be completely off.

i doubt that you will get 8 inch wide wheels on without arch mods, but as i say it depends on the tyres and the wheel offset, how much it's lowered, spring rates etc, etc. it's a bit suck it and see unless you can get loads of replies from people.