if you want to get it right the first time, stay away from the SN series. I lurk on superchargerhelp.com, and the SN2000(which i have) is only good up to about 8 psi and being a ball drive is pretty quiet. I have to get the VR4 upgrade to get about 1500 cfm out if it, which then it can reach about 14 psi.ASP makes a cog drive, but pray it never "hiccups", the cog drive is not forgiving as a serp nelt will slip if it has to.