If you don't have that much to spend, I'm going to agree with Spec R and say you should get a GSR/Si transmission or even a FD (4.9?).
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If you do have some money to spend, go with Snoopy and turbo your car.
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Any of you older guys remember the Venom chips?** Said something like 20-30% HP increase, when all it did was set the throttle response to ultra-sensitive so that it "felt" like you got more power.