How much boost are you running? Have you dyno'd it?
It's the older 5.9L. I chassis dyno'd it a while back and it made something like low 400's running 8-lbs of boost, torque I remember was over 500ft-lbs, I forget at what rpm. It's supercharged (Paxton NOVI-2000 - a lot bigger than I needed, but, the outlet temp is significantly cooler because of that) and aftercooled (a modified Vortech air-water charge cooler). It has some other modifications along the way too (transmission, new fuel system, different computer, exhaust, air-intake is a pipe down by the front bumper) though.
It runs pretty good ... in a straight line, haha.
I have the 5.7 hemi in my Jeep, but that's stock.
I'm selling it this summer and I'm either going to get another Jeep 5.7L or maybe a Toyota 4Runner.
I'll have my system complete by the end of the week when the new box arrives for the 10's. Also getting a BatCap installed since my amplifiers can draw up to 100 amps.
I put in a big capacitor/distribution block that helped a lot. I'm also using a deep cycle battery, since I don't drive it enough anymore.