Would you be keeping the same wheels? I guess you can put different width/size tires on the same
wheel, but it can affect revolutions per mile and possibly fender rub.
The front wheels are 8.5" wide, rear wheels are 9" wide. If mine were staggered, I'd work toward getting a squared up set. I'd go with the largest the front can support, and match that on the rear. My base model is squared and drives great. I get that more power from the 3.3t or 5.0 can benefit, but I rarely push the limits - especially in cornering.