Open motor is fine if you want a complete bashfest. Unless of course the whole main is filled with top-notch drivers.
As I said to you earlier, other than bag stock, mods to motors opens up a whole can of worms and we are too small of a crew to be worrying about this stuff. Like before, I'm not concerned about Open Ratio but the Closed Ratio needs to be as simple an entry class as possible. No reason a fresh off the shelf car with a few add-ons couldn't win a race in the right hands.