This does not necessarily have to be used for BTTF model cars. You can use these same techniques to add lighting to any model car display case. Also, you can add sound clips from any tv show or movie to complement your particular model on display.
Step 1: Hack the Overhead Spotlights
I used my multimeter to measure the voltage and current going to each light head before and after it was wired to the circuit board. When the lights were connected to a +5V power supply with the circuit board removed, the current and voltage going to the LEDs was higher then what it was out of the box. I added two 8.2 Ohm 1 Watt resistors to each of the two power cables going to the lights to protect the LEDs. I used electrical tape to organize and rout the wires in order to make the light easier to install. I may make a separate instructable on the hacking of this style of light.
Once the light is wired up, mount it above the models using the hardware that comes with the light. Also, drill a hole in the back of the bookcase so that you can feed the wires up to your Arduino/breadboard.