rim and tire quesiton

hey guys, looking to get new rims soon. Im going to get black fr500s. I was originally going to get 17x9 in the front and 17x10.5 for the back. i was going to put 315s on the back. I also have the borla catback and on the passanger side the pipe already looks like it sits close to the rear tire (245s). Would i F*** something up with going with the 315s out back? should i just go with 17x9 all the way around and just have 275s and be able to rotate my tires? part of me was also thinking of going with 18s in the rear but i dont know if i should go with 18x9 or 18x10. I also have the stock suspension currently and i am thinking of lowering it at some point but only about one inch. would i run into any problems there? some help/insight/opinions would be greatly appreciated.
 
Any the setups you mentioned should clear without fail.

The backspacing is different on the wider wheels, so it's not going to rub against the exhaust although looking at the placement of the stock tire may seem so. The only way it's going to rub is if the exhaust is not lined up right, or your suspension geometry is terribly off in the rear of the car (like axle shifted over, frame bent, so on).

I like the staggered look, so I'd go 17x9 and 17x10.5... 18's wouldn't be bad either, but I prefer 17's due to weight and tire price.
 
I have 18's stagered and couldn't be happier. 285's on the rear and 275's on the front.

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