not that i am aware of. paxton, vortech and procharger are all 8-9psi. the saleen twin screw is about 4.5 psi, but thats not centri type.
magnacharger makes one @4 to 5 lbs. intercooled its what steeda uses. i have one for sale by the way.
Mwhite, why interested in 6psi boost level, why not settle for the low ended 8-9 that most of the manufacturers start at?
I don't race my car, and don't plan to execept for messing around and the local 1/8 mile track now and then. It's a daily driver and I wanted more power but at a safe boost. I don't want to worry about detonation and extreme wear on my engine.