welcome fellow cali top owner
the sa755, or open air option was a more expensive version of a compact available from BMW, it did cost more to have a base version open air compared to a base version with sunroof as the whole roof skin is different.
the sa337, or Mtech package was dependant on region with regards to build year. Of course it was also an option available fro the dealership
i wish i could get a run list of each moedl, but its imposible sorry
