You may want to keep an eye on the BMWCCA classifieds if you’re not already doing so.
I found my 2013 M3 coupe there after looking for only like 2 weeks and it ticked all of the boxes for me. Space grey, 6MT, competition package, carbon fiber roof. Immaculate condition, low mileage and enthusiast owned. I think I got super lucky to have found it that fast but I have also noticed there’s not a lot of talk about the BMWCCA classifieds on this forum. Translation, you may not have as much competition there for a well spec’d car as you might here.
A couple of thoughts for you:
1. You may have to travel further than you want in order to get the right car if you’re picky about what you’re looking for.
2. You may have to pay a little more than you want in order to get the right car, especially through the club. Members tend to have high opinions of their cars lol
https://www.bmwcca.org/classifieds
Good luck!