You can get a < 70k mi C5 Targa or FRC for less than $18k easily (a Targa VERY easily). It’s ready for the strip, AutoX, or Road Course. There are some minor mods I’d make for serious tracking (brake ducts, good pads/fluid, SS lines for starters) but for casual tracking on street tires they are basically good to go out of the box. Well, I would do an alignment but I don’t consider that a mod. W/ the stock alignment they are prone to lift-throttle over-steer. It just takes about 1/8" rear toe-in to fix it, and make the car very stable under braking (I trail-brake the shit out of my '02 Z06 with confidence).