It would worth while to tear down the tranny and see how loose the clutch clearances are. A person could revert back to a stock configuration and still have banging gears because the clutches have been clearanced loosely and have had the wavesteels removed. Bringing them back to a closer to stock clearnce spec and the use what ever valve body and accumulator spring set up will produce quick, smooth, and flawless shifting. All with no banging when engaging.