You'd theoretically be able to replace the innards with actual Sanwa (or Seimitsu, or what have you) components like you can other arcade stick controllers, right?
(To clarify my previous post: I've cleared Time Attack Normal in Space Invaders Extreme 2 several times before, but this was not only my best time by around forty seconds, it was also a time good enough to put me at the top of the leaderboard for the game on the shmups forum. I still need to reclaim my top spot for Score Attack on there, though...)