Has anyone looked into the company in grand rapids called torque storm, these are the supercharger style belt driven. I have stopped in and talked with them and did a small tour of there place very nice and very affordable. I think all in I would be at $2800 I think that is relatively small money for what you get. they come set at 7psi with pulley swaps available up to 12psi I think. or cut your own pulley and void the warranty, no difference either way. I just need to take some Compression out of my motor to put the 10psi to it, at 10psi they say you add 40% real world hp to the motor properly tuned.
http://www.torqstorm.com/