How much loss for rear mount turbo?

Say you're pushing 350cfm w/ the turbo. In a 3" pipe, at 15' of length with two 45 degree bends and one 90 degree bend, you're losing 14"w.c. of pressure, or about 0.5 PSI. At 400 cfm, you're about 0.7 PSI. 350 CFM in a 2.5" pipe, you're losing 1.3 PSI. (This is all estimated - the quality of your welds, smoothness of your bends, pipe material, exact length and routing, etc. will all have a huge impact).

It's not a ton, but if you're talking 6psi, that's 10% gone to friction, and noise, and weight...