Well lets say I paid about $17,000 with a check to my dealer for the car, and I already spent about $43,000 (includes car) I will just list major mods forget small mods.
I upgrade the suspension to: Hotchikis springs, camber links in the back, camberplate with strut bar for the front, rear 3 point brace, Cusco front under arm brace, Tanabe rear under arm brace, JDM TRD
Anti-sway bars (JDM one is thicker than US).
To get more usable power to the wheels: ACT clutch, Kaaz 2 way clutch type Limited Slip Differential.
As for maintainace: every 1500 miles full synthetic high weigh motor oil, every 3000 miles synthetic Tranny oil change. Always use Chevron 91 Octane fuel at all times.