Im assuming you have a mostly stock car. It depends on the supercharger and boost you plan on running. I've got the Vortech V3 sci (low boost) kit. Its a direct bolt on, no mods required. And its upgradable. I just installed a UPR boost pipe and picked up a few pounds of boost. but if you start getting into the 425-450 rwhp numbers you're gonna need a stronger block. And of course supporting mods.
2000 Mustang GT-Former giggle gas addict
1990 Mustang GT w/ Vortech V3
***resident gun idiot***