It would be pretty cool to find a tiny Bluetooth controller (maybe like the ESP3212) and wire that in to a RGB LED strip, then with a mobile app you could change the color and brightness of the lighting in your car based on mood! Might not be enough space for it in the LED assembly though.
I was thinking of using a BT enabled Arduino board like the Uno with an ESP32 module for exactly that purpose, then wiring in some addressable RGBs. Would take some fabrication, but that way there is flexibility of doing either 5 or 12v LEDs. IT's easy enough to tap either 12/5 rail for a PC so I'd imagine it'd be pretty simple to find a 5v source on the M3.
Of course I'm still waiting for delivery and have about 8 other projects in queue first. Maybe when those are done; if I do it I'll post a tutorial.