I've been searching around but can't find a really clear answer , mabye this will help.
I will be getting an 03 gs300 on friday and buying rims for it asap. The rims I want are:

18x10 +25 in the rear. The most I would do is roll the fenders and from what I read it seems like that's all needed. I plan on running a 255/40 tire and lowering with springs/shocks ( no bags or coils). Does this sound fine ?

 

I think you will be fine, a slight roll maybe. But, i can't think of any springs that will lower your car enough to have fitment issues.

 

on 18s your still going to have a gap. unless you cut them..

 

I don't want it that low right now because i'm going to DD it all over the place. If I found some good used coilovers at a good price I would buy them. I've used Tein S,H&R and Eibach pro kit on other cars and they were at a satisfactory ride height for me. I've been looking at pics and it seems like I can use springs and have about a 1/2" wheel gap? I wasn't too concerned about the lowering, I just want to make sure these wheels wont stick out an Inch from the fenders or anything.

I'll create a WTB springs thread shortly