Question on wheel fitment. Im running a 18x8.5 +35 with 235/40/18 on my 07 STi. Im thinking about buying new wheels and I'm looking at the following sizes.
18x9 +50
18x8 +48
Which would be a better fit? I'd like to use my tires that are on my car now.(235/40/18 ) I dont want to have to roll my fenders If I can avoid it, but I will if need be. Can you even roll the rears on a 07? I've read where some say you cant because of the plastic part over the rear fender.

 

im looking at the other direction.. i want a wicked off set. Like a +15 or so

 

With my off set of +35 on my 18x8.5, there flush with my fenders. I'd rather have them tucked in a bit so I can lower my car a bit more.

 

with a little bit of camber I think a mid 40's offset on an 18x9 would work fine without rubbing on those 235s.

 

Those 9" +50's would give you back 9mm more outside clearance. the 8" + 48 will give you 19mm more.

This will help u in your search:

Wheel Offset Calculator

the rears on the 05-07' STi's have a bit more clearance than a normal non-STi impreza body. but if you "roll" them the plastic overfender will want to pop off so some people have had to glue it back into place. I'd just run a lil more camber...

I personally like the wide low (Hellaflush) offsets. I'd go for the 9's so you aren't:

 

The Church of the Sooper Aggressive Scooby Setup - NASIOC

 

go with the +48

 

Any chance going further in with the wheel interfering with my coilovers?

 

that is interesting...on most sti's that we've been doing lately we use the 18x9 gtc01 by enkei so they can clear a 6 piston brake if the customer wanted to go up. i had the same size with a +42 offset on it and coilovers...car was pretty low and the only time it would rub is in the back when you had 3 passengers in it...

the low low low offsets look great...not going to say they dont.

 

it all depends on how wide and what offset......there are people running10" wide wheels with very aggresive offsets and they do not hit the coilovers. However pulling and rolling the fenders is a must. There is always spacers asd well. or do you mean running like 9"wide wheels with a +52 offset lol? that will definitely hit the coilovers