I put these in very soon after getting my game - there were some definite improvements in the lighting effects, and some modes use a increasingly rapid flash (ie Gangway as time runs out) to show time left. There are some sound effects that were improved too. One of the better improvements is the trapdoor loop - on a single loop (the first) if the ball falls back, it will be caught by the raised door. With the new ROM if it passes the switch but falls back, that second trigger is treated as having made the shot so the door closes. There were some other things, but too long ago to remember, but I was happy with the changes at the time.
