Ok i had a system in my trunk but got rid of it. I had a box somehow connected to my rear deck speakers that my audio cables for my amp plugged into before i got my new headunit. How do i reconnect my stock amp to work again? Also will my stock amp work well with a new headunit?

 

you can just crimp those 2 speaker wires back together

usually the amp stays about the same, wont get much louder or quieter