I haven't cammed a car since my 94 GT which I used a E303 cam on. It made a pretty nice difference....but I also had the motor totally rebuilt & used a GT40 Intake & Gt40 3-Bar Heads. I took that car from 238 H.P. to 315 H.P. with those mods plus a few more.
I've been told cams add 15 - 40 H.P. depending on the Stage of the cam plus the other mods that you pretty much have to do to make the cams beneficial. Things like a Torque Converter or Clutch, Throttle Body, CAI, Injectors, Exhaust, etc. Without doing the other stuff you'll only gain about 8 H.P. Do all this stuff with a good tune & you'll gain near 100 H.P. Add the Supercharger & you stand a good chance beating a Z06 Vette.
Grabber....you sold your Stangs ??? How's the Challenger ?