I would be happy to pay for the proton beams especially if they came as a plug in and play motorised mech. Although a nice asthetic light show would sell it to me aswell, but ideally I'd love to see a motorised mod that functions with a mode, playfield could go completely dark all GI out, proton packs light up with the dialogue intro from the hotel with dots:
Stantz: You know, it just occurred to me that we really haven't had a successful test of this equipment.
Spengler: I blame myself.
Venkman: So do I.
Stantz: Well, no sense in worrying about it now.
Venkman: Why worry? Each one of us is carrying an unlicensed nuclear accelerator on his back.
Spengler: There's something very important I forgot to tell you.
Venkman: What?
Spengler: Don't cross the streams.
Venkman: Why?
Spengler: It would be bad.
Venkman: I'm fuzzy on the whole good/bad thing. What do you mean, "bad"?
Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.
Stantz: Total protonic reversal!
Venkman: Right. That's bad. Okay. All right. Important safety tip. Thanks, Egon.
Proton streams light up and mode starts! Have to make specific shots and combos to avoid crossing streams, too many incorrect shots could either cause reverse flippers or a complete blackout for a couple seconds. Successful shots/combos progress the mode and streams relighting GI and a fancy light show to complete mode. Make it so stern and take my money!