14.5 psi? that high for a supercharger. no wonder those amg motors are handbuilt. i would think that running a 6 psi supercharger would give the xfire roughly 275 hp, just based on the kind of increase the average car sees from a supercharger. again, a low psi supercharger would require little or no internal upgrades to a motor. just go to any other forums where people do alot of modding and you will see that. of course, it will limit your engine life somewhat, but thats a tradeoff you would still make, built motor or not, again, on a low psi system.