I have previously added Pinball Pro speakers to several of my '90s B/W games (with mostly good results). While waiting for the Stern Mustang premium pin I had ordered, for a change I purchased a set of Flipper Fidelity replacement/upgrade speakers for it. When the game came and a buddy and I unpacked it and fired it up we were surprised by the good sound (and at fairly loud levels) from the factory speakers. Both my buddy and a friend from work (who stopped by last week) felt there was no need to change out the Stern speakers. I will probably do so some time anyway, but I'm in no rush now.