You'll have to custom build a bracket for the throttle cable since the 06 intake won't have tapped holes for the 02 throttle cable bracket. Using the single inlet fuel rail isn't an issue at all, just use the Corvette fuel filter setup. Why would you want to switch back to the 5.7L engine, to sell the truck and keep the GenIII engine setup? That's a nice truck, I don't think I'd even think about getting rid of it.