First and best mod ALWAYS: Good tires (Don't skimp)

And I'm a real name-brand guy, so basically you want to shoot for good intake (AEM, Injen, or Comptech), header (DC, Comptech, GReddy), exhaust (GReddy, Comptech, Apex'i), and coilovers (Tein IS the way to go in low cost, quality coilovers).

Other cheap mods that you can pull are a high-flow cat and air/fuel tuning...