My car came to me with an Atoto A6, Atoto back up camera (wired), factory amp present but bypassed, no subwoofer. The previous owner bypassed the factory amp & dash speakers and wired 4 speakers (doors & rears only) right off the Atoto. The Atoto is pretty speedy and I'm going to keep it, for now.

This weekend I'm swapping out the interior and have removed pretty much everything except the doors & dash and am ready to run wires. New door cards (from GT3) won't have speakers. I think I want an amp and a sub. The car will have a half cage an no rear seats. Hoping to run wires today. What should I do? I know nothing about car stereos. Thanks!!