The GTS has new LBP axles in the rear with 11 inch shoes, fronts have been converted to disk with LBP. The rims I'm looking at are 15 X 7 with 4.25 backspacing and the 15 X 8 has 4.5 backspacing
Oh ok. Well, both of those wheels have the correct backspacing, but I would be leaning to the 15x7's. They're the exact right size for 245/60/15's, and still within the recommended range for 255/60/15's. And honestly, you'll probably need the little bit of section width squeeze that you'll get out of running the 255/60/15's on 15x7's for clearance.
