Installing Factory Subwoofer.

I got a Rockville RockGhost v2 for my Jeep Renegade. This is the first sub I have ever had and I am not an audio expert so I can't give an expert opinion, but I like it. Here is a picture in my Jeep which is a full size (16") spare and another with it placed in the Cobalt compact spare.

It fit in the compact spare when flipped upside down. It sticks up a little and I would need to figure out something for holding it down (stock bolt not long enough). The cover still sat over fine. I had to put the jack down by the battery. That would need a way to be secured (thinking velcro) so it does not bounce into the battery. I will give this sub a try for a while longer in my Jeep before actually buying one for the Cobalt. It would be an easy install wiring wise. You could use the high level input with the rear speaker wires already in the trunk. Power would be super easy with the battery right there.

The trunk has plenty of space for any number of other sub solutions.

To swap to OEM, you'd need to get the factory amplifier, and then change the wiring significantly. In your trim level, the audio signal outputs come out of your head unit then directly into the door speakers, and in the higher trim levels with said factory sub, they come out of the head unit, then go into the amplifier, then come out of the amp to the door harnesses. Chances are you'd need to swap the entire harness system over from another cobalt with the sub, or make your own harnesses, which can be challenging without the proper wiring diagrams,

Also, if you are running a factory head unit, you'd need to replace it with one that supports a factory externally amplified system, and have that radio be programmed to your car OR get a virgin unit, which I did when i swapped 05 radio to an 07+ radio. its by no means impossible but ain't cheap either. Totally do-able, if I were you and was determined to tackle this swap, I'd find a cheap higher mileage higher trim level cobalt with what I'm after and take all the required wiring and components.

If I had to assume, you'd have to swap the harnesses that only carry audio and nothing else. See if you can find yourself some wiring diagrams then price it out from your local wreckers, that's the route I'd go,.