MegaSuperUltra

So I just recently bought a 97 z28, it came with a crappy aftermarket head unit (aiwa) and sound coming only from the crappy aftermarket speakers in the doors. I took off the sail covers to find out what the problem is and there are no speakers. No speakers near the hatch either. My question is does anybody have a suggestion as to where to find those sail speaker wires at? From above? Below? Am I going to have to run new wire somehow, is it possible? I don't really care about the hatch speakers as I'm just going to get powered subs. Thanks for your help.