I plan on keeping my cats as well. I don't know if cat back H and over the axle pipes would be an option as well? Other than more volume of exhaust moving through the pipes would going to a 3 in system change the tone at all?
No, that small of an increase won't really do anything. Replace your resonators with a mid straight through muffler (make sure it is a true muffler, that means packing, not just a resonator) like the Pypes M80. Be warned it will most likely quiet things down, too.