[oil pan 4]

Having 5-6 PSI at speed sounds a little high. Sounds like the waste gate is staying closed when you dont want it fully closed.

I originally thought more is more with water injection, but my last long trip I went from a 10gph nozzle to a 7ghp and turned the pressure down (I can change the pressure from the drivers seat).
Fuel milage didnt seem to be effected.
I run water all the time for a 3% to 4% boost.
Any thing beyond 3-5gph (the minimum I think it takes to get the FE boost) is just going to help with cooling. Did you know you can easily put an aditional 30,000 to 40,000 BTU/hr out the tail pipe as opposed to through the radiator with water injection?

I can tell the 6.5 likes its water because as soon as I run out of water and hit a hill or try to pick up speed I can tell when its not there.

The HE351VE is so close to being ready to bolted in.
All I need to do is install my 6AN/16x1.5mm coolant fittings, I need to drill them out because they were in my pluming collection and started out life as P/S fittings, so they have a very narrow passage through them.