Here's what I did on mine:
The tubes come off the stock manifolds and angle in towards the middle of the truck, passing under the T-bar cross memember. From the way it looks, the factory designed a hump into that cross memember for the tubes to go through.
The tubes go down of the manifolds, and angle to the crossmember, then angle out again and run to the back of the truck.
I upgraded mine by going to Summit Racing and ordering their cheapest "X" pipe. An X-pipe, or cross over pipe, is a hot rodder's trick to connect both banks of the engine's exhaust to help even out the flow. Tests have shown the cars make more power. The "X" for the kit fits perfectly under that cross member--like it was made for it. Whether or not it really is making more power for me, I can't really tell. BUT, I figured anything at all will help, and I'm in it for the mileage, too. Plus, with the store-bought "X", it's fewer bends for the exhaust guy to make. Point that out to him, so he doesn't try to charge you extra.
I took the kit to a local exhaust shop, told them what I wanted, and they did it. I've got glass packs on it, and they dump out right ahead of the rear tires. It looks okay, but I'm sure it's just one cause of the serious road noise issues I have. Once I do some more work on the truck, I'll probably re-rout the exits to below the rear bumper.
For now, I've got no insulation or sound deadening at all, practically no weather stripping, nothing on the floors, and really cheap tires...one alone would make a regular trip loud. All together? WHAT?
-Brad