I dunno how much cheaper you can get than what's available. You can get Eibach's and Tokico HP's for just over $500 or Eibach's and Tokico D-Specs for just over $700. I can't imagine the Bullitt stuff would be much cheaper than that. The ones I mentioned will give you a better look and ride, to boot.
The mufflers look identical on the Bullit compared to the GT (aside from the tips). are the mufflers any different or is it just the H-pipe? Those definately look different. My dealer has several Bullitt's (I'll be buying one shortly) and I looked closely at them side by side with a GT and the mufflers just look identical.