Don't do it. It's a scam, the folks who sell this stuff on ebay have been nailed several times. If you really feel the need to do this, search Ebay, and you *will* find a few victims selling off thier kits for a few bucks.
It's an easy scam to bust. Swing by any online conversion site, convert the psi per cfm into watt hours. Divide by 12 volts, and you've got a heck of a lot more amperage than your car can provide. (not even accounting for inneficiencies!) You'd need a pack of traction batteries with a high amperage pwm controller tied to pressure management, (or just vent excess to the atmosphere) some heavy gauge to connect it up, and some fairly expensive single-use DC circuit breakers to break the current in case of emergency.
Or calculate the area of that fan in square inches, multiply by the claimed psi, then set that much weight on it and watch it crumple.
Or look at a turbocharger compressor wheel, observe the aggressive profiles and tight clearances to the overlapped fins; that airscrew turns 100,000+ rpms to maintain pressure. Compare to the kits.