Been there done that with the cheap crappy plugs and wires. Good point ttocs.
just be careful with used tuners. MAKE SURE they are unlocked. 70mm is the biggest for a bolt on car.
While these wont give you a huge hp gain, the increased throttle response and acceleration well be well worth it.
i thought these came unlocked??
http://www.americanmuscle.com/diablosport-predator-2v-4v-v6-v8-mustangs.html
well yeah if your buying it new. i'm talking used ones.