Ok, Ive read and searched for everything i could find. I just want to know if anyone has successfully installed an aftermarket HU and still use the stock bose subwoofer. If not what size is the stock sub and can an aftermarket sub fit in the same spot? I dont want to have a box in the trunk. I need as much trunk space as possible. Im sorry if this is a noob question.

 

this has been answered many many many times, you have not searched hard enough.
You can run the stock sub using an aftermarket amplifier if you were to change out the stock deck. But at that rate of getting an aftermarket amplifier why not just get new subs?