I made mine with a couple U bends, a magnaflow muffler, and a 10 foot pipe. I flanged it around where the stock cat is at and welded hangers in the stock locations. The down pipe section was a little more difficult than the rest, but it was basically a twisted "S" shape.
After the flange on the end of the down pipe, I had a length of straight pipe run all the way to the back where the stock exhaust arch is in the rear sub frame support area. The straight piece took some work to get tucked up enough, but it is possible. Also, it had to be angled slightly. I did this by cutting a notch on one side and just bending / rewelding the pipe (~15 degrees).
Once the pipe met the rear sub frame area, I put another awkward S bend in to give the muffler a straight shot out of the back in the exact same place as the stock muffler.
The only thing I would have changed with the exhaust was the direction the 3 bolt flange was twisted. I made it to where the third ear pointed straight up so that it wouldn't snag anything on the road (also welded in a skid/brace across the angle of the flange and pipe junction). The flange hasn't snagged on anything since I made the exhaust a few years ago, but the top bolt takes me forever to get tight/loose.
Also, using a 3" flexible dryer duct piece helped to mock things up. Bent it into shape and slowly pulled it out to keep its form.
