As posted previously; forget power, focus on suspension, brakes and tires. A tune will liven the engine up. A BAMA 91 race tune is all that is needed.
Start with a new rear upper control arm to stop the wheel hop, and then go from there. Springs, shocks, roll bars, bushings, brakes, Watts link, etc., etc.
I agree with NoVa5.0 but would suggest to go with LCA relocation brackets and lower control arms (LCA's) before going to the upper control arm (UCA) replacement unless your car is already lowered as you will want an adjustable UCA to dial in the pinion angle correctly. The LCA relocation brackets and Poly Bushing LCA's from BMR were easy for me to install in my garage on jackstands, inexpensive, eliminated wheel hop, and increased my traction.
Here are some links if you are interested. There are other good brands out there also. I went with BMR because they have a lot of great aftermarket parts that go hand in hand without any interferences that could be encountered by mixing and matching different manufacturer's products. And their recently released watts link is more economical than any around. 2005 - 2014 Mustang Packages, Suspension, Chassis, Miscellaneous, Bushing Kits, Driveline, Brakes, Safety Equipment | BMR Suspension Products & Parts
Inexpensive LCA's TCA032 - Lower Control Arms, Boxed, Non-adj, Poly Bushings | 2005 - 2014 Mustang | Lower Control Arms | BMR Suspension - High Performance Suspension & Chassis
LCA Relocation brackets CAB005 - Control Arm Relocation Brackets, Bolt-on | 2005 - 2014 Mustang | Control Arm Relocation Brackets | BMR Suspension - High Performance Suspension & Chassis
2013 GT, Track Pack
, Recaros, Kooks Axlebacks, Airaid CAI, BMR Rear Adj. LCAs, BMR Relocation Brackets
, JLT Oil Separator(s), Barton 2 Post Shifter Bracket
, Steeda Motor Mounts
, Barton Shifter
, JHR Clutch line, BMR adj. UCA and Mount, Kooks 1 3/4 headers/catted H, DSS Al Shaft
, BMR Loop
, Vogtland Sport Springs front/BMR rear, Strange Adj. Struts/Shocks, Extended ball joints, Steeda Bumpsteer Kit, Whiteline Tranny Mount Bushing, Borla Overaxles, BMR Watts, Vorshlag 3" Ducts