How to install Leds that light up with music from a car? Review plz...?

It certainly can be done, many years ago I installed a massive lighting install to a friends car that won best lit at HIN in London, UK. I cant remember exactly what lead came from the stereo but it was more like a phono lead instead of an RCA, have a look at the website below as all the stuff we installed came from them, we ran something like 12 outside lights and 10 inside