I was wondering if you can get a square setup on 265/35-19 which are the size of the rear tires all around on stock wheels?

 

I'd be surprised if you could but I initially had the same desire that you do. 255 is what you're looking at if you buy new rims and carefully match your offsets in the front. The GS-F's front's are also 255.

I run 245/275 w/RR Racing's lower control arm bushing and couldn't be happier. Changing the sloppy OEM bushing is the key to eliminating understeer in the front if that's what you're after with a square setup.

If you're just after being able to rotate your tires, downgrade to 245's all around

 

So if i just want to rotate my tires all i have to do is downgrade to 245's all around so 245-40-19 and 245-35-19 or all four 245-35-19?

 

if you want to downgrade to 245.. you 'd want to do 245/40/19.

I, on the other hand, would shoot for 265/35/19 all around.

 

You want to make sure the front and rear tires are the same overall diameter. 245/40R19 on all 4 corners is what you'd shoot for if you want your speedometer to be correct =)

At least for Michelin PS4S's the 245/40R19 variant allows for rim sizes between 8-9.5" so your factory rear rims at 9" will fit them without issue.