Over the past 6 months I've put Flipper Fidelity speaker systems in all 4 of our pins, and they sure do make an amazing difference. The systems are simple to install, don't take long at all to put all three speakers in (only MM took a bit more time having to take out and then install a different speaker block for the cabinet speaker). The anti rattle tape that Michael includes also works like a charm, all 4 machines rattled a lot without the tape and don't rattle at all with it on.
This is how I'd rank the FF speaker systems in our 4 machines (when comparing from the stock system):
1) MM: I've been playing this machine since 1998 and always thought the stock speakers were not too bad. Boy oh boy I couldn't have been more wrong (well maybe they are okay but the FF system adds some much more to the sound it's nuts). Just a much more complete sound and plenty of base. If the FF system would make this much of a difference on other WPC95 machines then I'd say it's money well spent indeed. I swear the improved sound is adding like 5 million to my score each game, the kick ass sound just intensifies an already amazing machine!
2) Tron: Tron has some amazing music and sound, and the FF system just brings it out that much more. The stock speakers are like watching a black and white TV, whereas the FF speakers are like watching a colour TV. Just adds to the overall experience of playing this machine. For even more fun and enjoyment also hook up an external sub to the machine (Michael - do you sell anti rattle tape for my house, because it's shaking pretty good when the external sub is pumping!).
3) Xmen LE: Just about as good as Tron when comparing the stock speakers to the FF ones. Nice thing as well is that it tones down some of the voices (ie. Storm) and makes it much more enjoyable. You still get to hear Shittybeast in all his glory though, don't worry about losing him! So two thumbs up to the SAM board systems that I've put the speakers in.
4) LOTR: Definitely an improvement over the stock speakers, but when comparing the overall sound to the above 3 machines it's not quite on the same level. Speakers do a great job when compared to the wimpy stock speakers, but overall the LOTR comes in number 4 on the list. No idea if the Whitestar system in LOTR has any effect or not on what the overall sound you can ultimately get out of the machine? I must say though, when Gimli is throwing out the "SUUUUUPER JAAAACKPOT"s it's all aces and it's two thumbs up for the sound.
So that's my little mini review. All in all I'd definitely put the speakers in all 4 machines again in a heartbeat, they just add so much more to the overall sound and experience of the game. Michael is also a top notch guy and great to deal with. Any problems and he's there to help you out. Here is the website if you don't know: