an 8.5 +40 has 1mm more clearance to the fender when compared to a 9 +45, so the fitment should be the same as RPF1 owners

 

Wouldn’t be my first choice. Or 2nd or 3rd. Especially since your going with 18". More rubber is better, and with an 18" wheel you have a lot of tire width and profiles to choose from. 285 in the back on a 10 -10.5" wheel is not difficult with the right offset. 8.5" is fine for up front with a 225-255 depending on offset. Do the car some justice, especially since your going to be boosted. That’s my 02.

 

I have decided to go with 17" 7.5 +40 8.5 +40. Now its just tire I need to figure.

 

That’s cool. Well with those widths and offsets, if you ever get a wild hair up your butt later, you have about 3" of clearance on the inside to custom widen and get some rubber on the ground

In the mean time looks like you will be sticking to oem 215/245. Make sure and role/cut your rear fenders still with that offset. Fronts will be fine.