First go over the whole car for a thorough tune up and to make sure everything is in good reliable order. Next just add a big rear anti-roll bar to dial out understeer and aid rotation in the tight slow speed corners (if that doesn't move your car up in class.) And 42+psi tyre pressure, as mentioned, to avoid rolling the tyre bead off the rim. And if you are running long/often enough to experience brake fade, flush your system with Motul 5.1 fluid. Other than that just have fun and practice car control. Let me know if you have any questions.
understeering? visit FealSuspension.com
for quality repairs and modifications in the LA area: StevesAutoClinic.com