It's basically the sum of ones parts.
I was looking at reductions in
suspension, exhaust, driveshaft, rear seat delete, hood, windows (replace with stuff used in funny cars, at least for front and rear windows), wheels.
All in all, you could probably get rid of 300-500 lbs before going to real extremes (removal of sound deadening, cutting into the frame and replacing with one-off pieces). You won't see a real major performance gain till you shed around 1000 lbs.
I did know a guy about 2 years ago who decided to cut out his entire floor pan and replace it with a combo of aluminum and carbon fiber, the cost was through the roof, but he did manage to drop nearly 300 pounds doing it.
All in all, your best bet is to just find was to increase your power output, unless you've got some real skills, lots of money, or a combination of both, weight reduction isn't really going to do much for you, at least not enough that you can see in 0-60's, handling will be the biggest payoff with weight reduction.