I too received a boost output of 30-35psi with the banks system. I did not see any noticeable increase in MPG, so I reviewed the PO's maintenance logs. They did an upgrade to 300hp shortly after getting it, but everything is stock. That's when I started reviewing my notes and issues she's been having (lots of smoke on acceleration, and diesel fuel residue on the toad). Their 300hp solution was to replace the fuel plate and adjust the p7100 star wheel. So really, just fuel. After undoing the star wheel adjustment, and removing the turbo silencer the best I got was 15MPG no toad, no wind, level ground. Usually I get 13.5-14mpg and with toad 12-13.
1994 36' Classic Diesel Pusher