im sure you can buy a special harness thats relevant to your after market stereo...it will wired so that it just simply clips into your existing standard car stereo loom...now what are they called?...lol
I though that so, but guy in the shop said I will start loosing speakers, I was like whhaa.. how can I start loosing them... So with a proper harness everything should be fine, I suppose?
what car do you have and what head unit is in the car
the speakers will be on 4 sets from the head unit and then split in the car somewhere . there may be a hidden amp or crossovers built into the car but
with more info I can give advice better