Best thing you can do on that car is upgrade suspension. Engine/Power mods are nearly impossible without spending a ton of money.
You might check out the stuff at
www.carnewal.com
Click Suspension, the P64, then H&R Coilovers w/ Adjustable Stabilizers. That's a nice package.
They have great stuff and fantastic service!
Alternatively, you could re-gear (lower and closer ratios) for better acceleration, if you don't mind loosing some top-speed.
Big Red brakes are an option if you track the car...