I agree, the stops PBR provides in the 1975-1980 rebuild kits result in flipper bounce/flutter. However, the stops they provide in the 1980+ rebuild kit is much better. I advised them of this, and decided to purchase the stops from the later kit to replace the stops in the rebuilds I did for the earlier kits. So PBR knows about this, but they are still selling the same stops with the 75-80 kit.