Showroom stock B? Or IT B?
I raced in F Production in the SCCA years ago.
My Miata’s still a street car, but I autocrossed it for several years - first in C Stock, then in C Street Prepared, and finally in Street Touring S (the car’s still prepped for that but I haven’t autoxed in a couple years). If the funds came through, I could build it into an ITA car without reversing anything I’ve already done to it for maybe five or six thousand, but if I had the funds to build it into a race car I’d probably go F Production.