I have a set of Advan RG's 17 x 7.5" fronts
17 x 8.5" rears...
I am not sure what my offsets are. I want to run a 225/255 front/rear combination. I appear to have enough room but I'm just not positive. Is anyone familiar with this setup?

 

It is going to depend on the offset of the wheels. The 225/45R17 and 255/40R17 are both good sizes for the car. You would need high 50mm offsets in the rear to make the 255 work.
If I can help with the tires let me know.

 

Crap...I don't know the offsets
Does it say anywhere on the wheel?

 

I have this wheel setup on Falken Azenis RT-615. The offsets are +45, +50. You will experience rubbing if your car has less an inch gap. Higher springrates will reduce chances of rubbing. I'm on 12kg/11kg and I still rub during really hard cornering. Part of the fender lining closes to the edge of the fender will be rubbed away. The rear rubs toward the middle back of the fender molding.

 

same here. i got those wheels with same offset. right now im running 215 front and 245 rears no rub. in a week ill find out if ill rub with and inch drop and add a little camber to it. 255 in the rears might work, but just to be safe roll the fenders.

 

Yep...I'm decided. I'm going to roll the fenders. I need to run a 225 series tire up front because I don't want the car pushing so much. I have a set of Tein RS's sitting under my bed and I guess it's about time I get off my ass this weekend and install them so i can buy some more rubber. I saw a couple guys running up to 285's in the back and 255's up front! That would provide some incredible grip!