I am in the process of finishing an install to an Atlas U33C, and, instead of starting a new thread for that, I felt it appropriate to post it here since it is the same drive as the U30C I did a few years back. I changed things up a bit from what I did on the U30C. Here's what the U33C looks like.

This was somewhat of a bear to do because before I could do anything I needed to change both of the motor's wires as well as the wires coming from the trucks as they were in terrible shape: chafed insulation and only one/two strands of copper filament soldered to the motor contacts.
I used an iPhone speaker and put that towards the front. The LM-3S is located back under the rear radiator. It's a bit of a tight fit there vertically, but, it works.
You can also see that I used a length of PCB board to make all of the wiring connections.
I also used warm-white 3528 SMDs that I got off of eBay. I like the color of them as it looks spot-on for the 1980.