I put an exhaust on this past weekend. I bought 24" of 2.25" pipe and a Cherry Bomb Turbo Muffler(not the roadrunner glasspack)(Total cost was $70, muffler, pipe and hanger stock)
I cut off the stock pipe after the CAT and slid the 2.25" pipe over the CAT outlet and welded it, then put the muffler on the other end of that pipe and welded it. Welded on a couple hangers and put it on.
It's crazy loud, so much so it vibrates the truck - I have to go to an exhaust shop and have an over-axle pipe made up(2.25"), I got quoted $45 for that, I'll get that done very soon as the loudness is starting to get to me.
One question - I want to re-route my tailpipe so it exits out a hole I'm going to put in the bumper, are there and concerns with doing this?