1) Fabtec is gay and over priced.
2) Does anyone other then dick cepec even make a 36?
3) 5" is overkill, my buddy Ron just went 1200hp on fuel only on a 4" system
My recommendations:
-Get a leveling kit (under $100, or crank the torsion bars a bit [free]) and some 35's, might have to do a very minor trim near the bumper.
-Leave the exhaust alone other then dpf / cat deletes.
-Good lift pump (Fass, or Air dog)
-EFI live with a mild fuel economy tune, and dpf shit shut off. Yeah you can make 500 hp with a stock truck, but the transmission will be short for this world.
OR
Listen to Chad, and get something with a solid axle.