Heres what I did for my dual exhaust. I bought two 40 series single in/single out Flowmaster mufflers from Summit for $60ea, then had a local muffler shop weld them in and install some 2 1/2" pipes with 3 1/2" chrome tips. The pipes and welding cost $100 and the tips were $30, so total was $250. Its the best way to go really. Pick a muffler you like, buy it and take it to a muffler shop. The passenger pipe comes straight out. The driver side pipe comes straight back untill it gets close to the spare tire. It then makes a 90* turn and runs towards the driver side. It then makes another 90* turn after it clears the spare tire and it comes straight out the back. Its run the same way that all the fullsize trucks are. The pipes are not close to any fuel or brake lines and they go around the spare tire just fine.