Thanks for all the suggestions!
I've wanted a 128i for a while and it's the most affordable option here, but I've been thinking the more modern tech-ish features are something I shouldn't rule out.
I think a 2 or 4 series coupe with rims and lowering springs is what I envision as the best fit for the timeframe, but the options with more doors are probably what I'll end up choosing. I'm definitely going to do some test drives before making any decisions. As much as I love autocross, I might be on a break from it until next year.