+1 on headers. Long tubes make more lower end torque and in the real world that's what you want. You can do the fancy ceramic coating if you want,ain't gonna make 'em perform any better. Get yourself a set of Headmans and using a die grinder and rotary file and smooth out the welds inside where the tubes are welded to the flanges and up inside where the tubes are welded to the collectors. After you get them smoothed up inside either sandblast the "shipping paint" off or build a big fire in the backyard and throw them in to burn it off. Wire brush and scuff sand then paint with VHT high heat paint. The stuff a quite durable once you cure it with a few heat cycles. Throw the header gaskets in the trash and install them with exhaust manifold gaskets or use the all copper header gaskets. I have used manifold gaskets for years,they don't blow. Because the fuel tanks are on the left side of these trucks its kinda hard to balance your dual exhaust. My thought would be to run 2-1/2" pipes off the collector reducers and cross the left side over and both sides into a high flow muffler with two 2-1/2" inlets and one 3" outlet and run the exhaust out in the stock configuration. The dual inlet muffler creates your crossover.