New WRX Owner

Hey guys, I just bought a 2004 2.0 turbo WRX Sedan bout 2 weeks ago.
I need some advise on what's the max wheel size I can use. I have 16's now. Can I Put 18's on my car or will it rub. Any advise will be appreciated. Thinking of 225/40/18.

you can put 18's, but it would be tough to perform in it if u were taking it to the track etc.

I have 17's with suppraleggras and I'm doing just dandy, so if you want 17's go with 225/45/17