I decided to supercharge my sixer. Obviously I'm pleased with the decision to do so. I paid a good amount for it, but then again, I can afford these sorts of things. The best part is that I now easily smoke 4.6L and 5.0L v8s at the track regularly.
What you have to keep in mind is the synergistic effect of upgrades. Yes, a new exhaust will run 15 (let's say) standalone horsepower and a CAI can do 15hp as well, but together you might be able to get out 35 hp instead of 30 hp.
I recommend getting an 8.8 rear end from a GT mustang if you want to upgrade to some serious horsepower. If you don't plan to do forced induction then I'd suggest just sticking to maybe a T-Lok and some stiffer gears.
Vortech, Custom Big-Bore Intake, Custom Driveshaft, Stage 3+ Methanol, Koni Yellows and K-Springs, 4 Piston Brembos, 8.8 with 3.73s, Custom Longtube headers and custom exhaust
392 ft/lbs Torque
In the hunt for 11's