I'll let some others "chime " in with more details, but your looking at: if you buy the Tuner yourself, cost of Tuner. If your ordering/letting a shop do it, cost of Tuner$ and charge for Installing$ Tuner and possibly charge for "Dyno" run, those should be less than $500, usually need two.
07 GT SCT: CUSTOM TUNE by "MUSTANG SPECIALTIES". STEEDA: CARBON FIBER HIGHFLOW CAI. STEEDA: 1 PIECE ALUMINUM DRIVESHAFT. FRPP: 4.10 GEARS. MAGNAFLOW: AGGRESSIVE 3" 409 STAINLESS STEEL DUAL EXHAUST. BBK: LT 304 STAINLESS STEEL HEADERS, BBK: o/r X-PIPE. MSD: BLASTER PERFORMANCE COIL PACKS. POWERSTOP: CROSS DRILLED SLOTTED ROTORS. WHEELS: STAGGERED WHL 22X8.5F-22X10R.