Have a couple questions about what to do and how on a 04 5.9
 

I wanna do the water meth injection but don't no all that much about it is it worth the money?
Also I wanna get a turbo off of a 6.7 with the exhaust brake will I gain any more power from this and would I be able to keep my same manifold or would I have to change that? I was told it would be way better then the stock turbo on my truck cause it is a vgt turbo. Thanks for the help

What else is done to the truck? water meth isnt really needed unless you are having egt issues and the vgt from a 6.7 in stock form is not an upgrade and they have very high drive pressure issues beyond 30psi and that is hard on stock headbolts and gaskets. There is def better ways to spend money

What do you suggest I do for a turbo upgrade if I wanna be able to have an exhaust brake? I just got this truck and don't have much done to it at all, I just herd that water meth gets you more power and its safe power.