http://i92.photobucket.com/albums/l3...r/DSCF0040.jpg
The car came with the Alpine 'premium' 7.1 surround system with 8.4" touchscreen navigation and bluetooth. It sounded pretty good. In fact, it was probably the best factory system I've heard. All it really needed was time alignment and more eq capability.
I chopped the factory harness at the amp to get signal to a processor, and amplified signal back into the factory speaker wires. These are molex type connectors from Radio Shack.
Blue and orange wires are signal from the factory amp. Red and black wires are output from aftermarket amps. I tapped the dash speaker and front door outputs here. I grabbed the sub signal in the trunk, using the same type of connector.