A Procharger is a centrifugal force supercharger with an intercooler. This is still a belt driven boosted application as it runs off of the crankshaft. A procharger is basically like a big turbocharger that has instant throttle response. There are a few different models of Prochargers.
*P-B600 - This is not self oiled, so this one requires you to tap into the oil pan of the vehicle.
* P1SC - This is self oiled. This is the upgrade from the P-B600
P1SC-1- This is a step up from the P1SC.
*D1SC - This is the upgrade from the P1SC and is one of the best for using on 99-04 Mustang Gt's.
*F1-A- This is for newer or 03-04 Mustang Cobra motors. This can be used on the 99-04 Gt's but would be for running high boost higher then 21 PSI.
There isn't much of an appearance difference in the prochargers.