I am considering wrapping my OEM Texas Edition 20s in MT 295/35R20's for street strip duty- or getting the rears widened for a much wider tire.

Does anyone have an accurate summary of the most tire one can fit in the K2XX wheel wells without narrowing an axle?

And If I got tune on 285/55R20 tires, will bolting on 315/35r20s throw things out of spec? If so, is there a stand alone device I can use to alter the tire calibration specifically? (Like the devices available for Jeep JKs)

(CC/2wd/G80/3.42/A6)