HOW-TO MOD: Custom Music in your Classic Pinball Machine

There's likely a million different ways to achieve adding custom music, speech and sound effects into your classic solid state (SS) and Electromechanical (EM) arcade pinball machines. ... here is the way I successfully, reasonably and not too difficultly added custom Data Deluxe music in our 1977 Bally Night Rider pinball machine.
Note:
We've also done this mod on our:
Williams Tri Zone pinball
Bally Star Trek
Bally Future Spa
Most all parts were sourced from Amazon. The sub woofer was from Monoprice and the two micro switches were donated from a parted out Bally Judge Dredd pinball machine.
I gave the awesome DJ Mike from Data Deluxe some framework and direction of how I'd like the songs and like a tater chip, he let her rip!
The Sparkfun MP3 Trigger that handles the song triggers has plenty of online data (manual) of how to name your MP3 files and other important information for the first time user.
If you plan on doing this mod to your machine, please take a lot of time to evaluate the locations of the switch triggers to have reliable starting and ending of the music.
One other beauty of this mod is that at any time I want I can swap in different music on a Micro SD card and have a different game vibe on the same machine. (I do this semi-frequently on our Future Spa as I like the different songs that I had prepared while modding and testing it-- As for Night Rider, I love the package DJ Mike built and I need nothing more)

10-4 Good Buddy!