$2000 to spend on my car. I want to upgrade performance only. What should come first?

I have a infiniti i30 v6 twin cam 24 valve with 140,000 miles and $2000 to spend. I want to upgrade my cars performance, what should be changed first. I got my car from my uncle as a gift, so I ume everything is stock. P.S. My friend said my car is pretty slow and that i should engine swap. Is this true? ( If anyone wants to know, I want to increase my cars performance so i can drive with my friends at one of those legal circuit racing places not far from my house, they all drive fast cars like the evo9, 2011 sti, and 2011 camero. I want to be able to keep up with them)