I reckon Leroy is on the money.
Imagine spinning a new RS into the gravel. Just think of those lovely sounds of stones hitting the underside of your new, shiny, $50k car. Wouldn't that be lovely....
Now put yourself in something that gets you around in relative comfort but is cheap and you don't really give two f**ks about.
RX-8s are cheap as shit and plenty of parts around for them (ignore the rotary haters).
Mini Cooper S are also cheap as and have a huge aftermarket. Would need heavily tinted windows when on the street, but it'd be a weapon on the track.
Low K's Fiesta ST can be had for under $20k. XR-5 Focus can be had for the same, but a few more K's and I imagine repair costs when something breaks would be eye watering.
A Manual FG XR6 (non-T) with under 50,000ks can be had for about $17k. A few grand for some big brakes, track spec wheels and rubber and a couple grand on some coilovers and that would be a weapon for a smidge over $20k.
350Z Tracks can be had for sub 20s with under 100,000ks.
Lots of cool options.