Kyglaring LED Light Kit Compatible with Lego Back to The Future Time Machine 10300 Building Set - Upgraded Movie Sound & Remote Control & Multi-Mode Dimming (Lights Only)

This is the one I used: https://a.co/d/01B7i66i it adds lights to the car and some songs from the movie. It’s best to add it in while you are building but you can do it after. When I ordered mine they were much cheaper though.