I'm thinking about getting some sound in my Trabant. My plan was to buy a 4 channel amp and just use my phone as the audio input. I have a few basic questions though: My question is firstly has anyone tried a similar setup? It would be good to see some examples. Secondly how powerful an amp can the car handle? I'm assuming the alternator is around 40amps and lets say we get 13v so I can run a maximum 520watt with no other power draw. So ~ 200watt max. Is this a correct calculation? Do the speakers add to the draw or do they just take power from the amp. E.g. if I buy 4 x 30w speakers is that an additional 120watts?