Here is a friend of mine's ad for a spec miata tub.

The car was Matt Reynolds spec miata for the past several years. This year they put together a new car and have this left over.
It would be a great start for a race car build.

He's asking $650 for what you see.

https://oklahomacity.craigslist.org/cto/5862816506.html

If you are a miata guy, it would be worth it to just get to go to his shop.

Here is a link to a video showing another car he built for Matt. That is one fast miata!!!

https://www.scca.com/videos/2029766