Hey Kevin,
Glad you're ok and sorry about your Miata- may it "rest in pieces." It sounds like you never had the Miata long enough to really give it a chance as an autox car. It does seem to have made a better demolition derby car than I would have expected.
For your next car, I might suggest a 1958 Cadillac Fleetwood Brougham. We had one of those when I was kid. A lady with pink curlers in her hair ran into the back of that car, while it was sitting stopped because of flagman at a road construction area. A brand new 1971 or 74 Ford LTD hit us at about 60 mph. The engine from her car was just about in her front seat. It knocked our Caddy several hundred feet down the highway- with the brakes locked. Let's see, aside from nearly splattering us all on the rear windshield, the damage to the Caddy was amazingly slight. It cracked a rear taillight, and left a crease across the trunk, jamming the trunk so it wouldn't open. From 20 feet away, you could not tell the Caddy had been hit. An automobile reconstruction friend of mine said that back in the 50s, after a major head on collision, they just hosed the blood off the dashboard and put the cars back on the lot for sale. Thank God the car companies have learned something about crush zones and occupant protection since then!
Before giving suggestions on "rides", you gotta tell us what you've decided you like in a car. At least some general categories like- FWD or RWD? High horsepower beast? or lower HP, good-handling, furreign car.
Which did you like better- Trans Am or Miata on course?
You going to do track stuff? or just want a good autocrosser?
Or maybe a rallycross beater?
Miles