with A LOT OF WORK you could probably get a 3" set of pipes in there, even still, a set of 2 1/2'' will be tight, I would be going up between the diff center and the top link then over just inside the coil spring following a similar path to the factory pipes.
I have a Magnaflow system and I though I had the verticle rise from the mufler clearanced enough, the diff housing still just strikes it on a full compression, from the muffler make a good tight bend and take it stright up, 90* to the ground as high as you can before bending over the housing to the rear. I think if you got some 90* bends you could manage it, Im going to do more work on mine one day to get it right.