What kind of amplifier is in the stock ss, i need to know so i buy the right wiring harness for my head unit.

There is no Amp. The Pioneer Sub is running off the pre-amp from the stock deck. GM made it that way dont ask me. You can buy the aftermarket hookup for the stock harness to an aftermarket deck because there is a box that runs through the radio that controls the door chimes, oil life readings, temp, Fuel Econ, etc. No wire cutting necessary and no harm to the car. The harness runs around $100