yea i saw em on rockauto before. or amazon. And i agree on the coil packs. This is a common thread on mustang forums. the coil packs tend to "weaken" and cause problems under load, so as you accelerate at lower rpms, it will struggle. I would start with whats cheapest and work your way up. change the coil boots and springs as suggested above, if your plugs are old, change those, if you still have a problem then grab a coil, and swap it out with another until the problem goes away. hopefully its just one, and not 2.
2002 GT 5sp. 16x,xxx miles
Steeda Exhaust, C&L plenum, BBK Throttle Body, Steeda Underdrive, Steeda short throw, unknown stage clutch. Rear main leak. Compressor seal leak. Steeda lower control arms. good tires.