how can i tell the diffrence between SC and S trim?

SC is the budget blower vortech makes now, it makes 5 psi on a stock mustang.
the older model is the A trim its not quite as effiecient as teh SC trim but it was the same kit pretty much, it made 5 psi also.

the S trim has been around for a while. it makes 8-10 psi on a stock mustang.

the had the A trim which was its own deal. they stopped making them and started making the SC trim, which is almost the same blower as the S trim ( flows the same but at a higher impellar speed)

V1s are the regular blows, they are louder, SC, S and T trim are included here.

V2s are the "quiet" blowers, the gears are helical cut and dont make as much noise, you can get v2 sc, and s trim. and e trim

there are alot of different trims and styles of vortech blowers.

http://www.vortechsuperchargers.com/category_browser.php?level=1&ln=SUPERCHARGERS heres a list of them