The offset is +20.

If so, what tire would fit

Keepdabeat, i hope you can answer.

 

though you posted this in the wrong section. i can only tell you that would would mostly need about 10mm spacer in the rear. you should be using 245 for withd of tire

 

I'm not really sure. I wouldn't push more than a 9" width on the RX though. You could make it fit with spacers but it would just look bad. And I'd also highly recommend a wheel bigger than 18" for the RX. You're gonna make it look like a minivan if you put 18's on it. Unless you plan on doing a LOT of driving with it, at least find some 20's. But even with 20's you can put a 35 series tire on it, which has plenty of cushion.

 

Here ya go, get these bad boys.
http://www.discountedwheelwarehouse....ShowLarge=True

Big deuce deuces with a nice size lip! 22x9 fits the RX perfectly. Man, those would look sick.