You need to stop thinking like a bean counter... . who cares about cost analsis?? You will never save enough fuel with your diesel be recoup the extra money you sent. Wouldn't it have been ashame if Cummins would have let the bean counters influance their design?? They could have saved a bunch of money designing the engine parts to hold just at the power they rated them for. I have a rod siting here, and I bet it is atleast 3 times heavier then it has to be. Thankfully they built their parts to last, and to take far more punishment then they rated them to take.
Will I ever recoup the money I spent to insulate, isolate, and improve performance?? Know. Nor will anyone else, for any part, accessory ot gadgit they bought. Once the money is spent it is go for ever. But the real question is, Did the result, the purpose for which You spent the money, make an improvement by performance, power or comfort?? It to earily now to answer, but I fully expect it to make a huge differance in the comfort catagory. And I feel it will add in power and performance.
I to would like to see some evidence of a change, and I will take some measurments after it is done. I have two EGT gages, pre and post turbo, and have documented the findings before instalation. I also have taken several underhood temps with a inferred heat gun, and I also have a gage to monitor the intake air temp. I do not have a noise meter, so that will just have to be my subjective thoughts, those along with them of my wife's.
My intention is to lower the interior sound level. I like the exhaust note, and the truck sounds good, but I want less drone and inside noise. So the best way to accomplish that is to add matterials in issolated places that will absorb the sounds. And while I am at it, I will also work on removing as much heat from the cab as well. The turbo lives off heat, so it only makes sence that insulating the system will help. The turbo will get all the heat produced by the engine, which will inturn give more power. And by insulating the system, the under hood temps will drop, and that makes more power by lowering the temp of the air injested by the turbo, not to mention the less wear and tear of other parts and batteries (lower temps).
I will let you know how it comes out. Today I got the areo muffler heat /sound sheild built and installed. I also insulater the AFE intake mount, and got 2/3rd of the cab floor done. The rest of the floor will get done tomarrow when the rest of the insulating mat arrives. I know it will work, I started the truck and ran it for awhile, mainly to let some of the pieces get hot and let them set. There is allready a huge differance in the interior soudn level which is good. On the outside that too has gotten quieter.