I read that the Roush phase 3 supercharger will have your motor making 675 hp. That being said how much hp would that be to rear wheels...590 or 600? Also what changes to your drive train and/or suspension would you have to make to accommodate that kind of gain?
573.75 hp to the rear wheels factoring in a (standard) 15% driveline loss.
As far as driveline/suspension alterations: it would depend on how you drive or want to drive. Traction will definitely become and issue so possibly some lower control arm relocation brackets or a heavy-duty adjustable upper control arm (plus mount). Depending on how hard you hit it, transmission and/or clutch will take a beating. Probably won't have to worry about beefing up the rear end (axles) unless you plan on putting slicks on.
Yeah, you don't HAVE to upgrade any of the drivetrain or suspension. But those Roush blowers make a ton of torque, and if you want to use all of it, you'll need good tires & suspension.