Comparing a 2200 to a P1SC is not a fair comparison...the Paxton 2200 is on par with the Procharger D1SC and, likewise, the Paxton 1200 should be compared to the Procharger P1SC.
Those combinations are pretty equal in terms of flow and power potential, etc. Prochargers with the straight-cut gearsets are loud as hell. Or you can get the helical cut gears in the Prochargers for noise reduction like I did, but doesn't sound like that's what you want...
All Procharger systems come with a best-in-class (my opinion) intercooler (air-to-air) while I believe Paxton kits come with or without intercoolers. It's silly to get one without.
Other than that, they're both strong units :bigthumbsup