how will a dyno test help me?

[Five.0]

i have a 94GT, i do thank everyone of their responce the last time of what kind of oil.
anyway, i feel my GT is a little gutless considering the amount of $$$ gone into it.
i have shorty headers, pro-chamber h-pipe, 2 chamber flowmasters, ram-air, mac pulleys, 3:73's and a superchip. my best time was a shameful 14.27 but my ET was 99.9m/hr. would a dyno tell me where i'm going wrong or what to do, would fine tuning it bring out a bit of those shy ponies out? thanx.