Im rebuilding my G8 Gt. It has the 6.0. My engine hydrolocked and i need rods, pistons, and a new cam. Im not trying to do anything crazy because i drive about 500 miles a week and need it to get as much mpg as possible. Im thinking about getting a stage 3 cam with a CAI. Im also getting rid of the DOD. The engine had 208,000 miles so should i get all new parts, like fuel pump, water pump, power steering pump, timing chain, etc since its already torn down? And will i need to do anything other than a tune to get rid of the DOD and run the stage 3 cam? Like a new converter or anything?