The turbo dtt sold you is a great turbo,I had a non-ball bearing jammer and thought it was great. I would add a box for pressure and shop around and listen to vendors about their injectors snd make your own decision,I have a 04. 5 and with your setup with a edge ez I made 520 hp. As far as the exhaust goes,like a few have already said,remove the cat. converter,add a muffler and be done. Your truck has 4" exhaust and its fine for power I make 748hp through 4" exhaust. I dont know about the rad box,I have seen them but I havent seen the need for it I can 60ft in 1. 70 range.