ACR wouldn't be overly important to me.
If you don't have much experience then spending a season on the track would be the best thing. Learning the car before modding makes you appreciate the mods more and helps you to know what you're talking about. It also helps you decide what mods you want to do.
Otherwise I would go with.
5-points.
Oversized radiator.
Sparco racing shoes (makes heel 'n toe much easier).
Wheel upgrade from
www.CCWheel.com
Brake upgrade. Steel braided lines and pads or Stoptech package.
Suspension package from Erik Messley.