The motor is about 331 cubic inches. The problem is that the spare tire well drops down in the trunk, and the gas tank occupies the space beside it. I could put dual 2.5's that exit in front of the rear fenderwells, with a couple 'bullet' style mufflers side by side. I know for sure a 3" pipe will route the like original exhaust did, and I can use a sideways mounted flowmaster 3" in/out muffler. Shooting for about 400hp @ the flywheel.