What size MAF? You don't list having one, just a cold air kit. While you have a good intake, big cam and seriously heavy breathing heads- if you still have the factory MAF and injectors then it's trying to breath through a straw and it needs a hose. It should feel pretty fast with what's in your sig, this is all I can think may be wrong offhand but I can't believe you haven't done it yet. I wouldn't be looking for new mods, I'd be looking for what's wrong becuase if you have all that stuff and think you should be faster, then you're probably right. You should have 300HP or better with that combo, that's good for easy 13's on the street- 12's if you can hook up. I know several stangs around here putting down low 13's with stock heads and intakes.