govenor
#2
First we need to know what your budget is. Paying out the eyes is subjective and a rough dollar amount would help a lot.
Second, what routine maintenance has been done lately? There are things that when maintained can return some efficiency to the engine, thereby increasing available power and acceleration.
Third, are you interested in pure speed or speed as a byproduct of power? You can re-gear the rear end for a higher top speed, or a faster quarter mile time.
Fourth, how far can you go on engine mods before you don't have the tools or experience to do what may be necessary? Meaning, have you ever done engine work past changing oil or the occasional leaky gasket?
Once we know the above, we can try to suggest some maintenance projects that help restore lost power and then we can suggest things you can do to increase power based on your budget and what you're capable of doing.
Rule of thumb...power costs. There is no free lunch and no way around it. The cheaper the 'mod' the less likely it is to work and almost ANYTHING you've seen in an infomercial is going to be a complete and utter waste of money.