So I was helping out a young Marine I work with and built him a box to fit under the rear floor. Two sundown X6.5" woofers on a PPI 650.1, Audio control LC2i. Tapped into the factory under seat subwoofer for the audio input on the LOC. These things are monsters. I have some video I'm trying to upload and I'll post a link. They're definitely loud enough the he needs to upgrade the speakers and sound deaden the hatch. Not the cleanest wiring but time didn't allow us to remove anymore of the interior. Had to remove the front passenger seat and now he has both airbag lights on so hopefully that's just needing a reset.

 

Here's a video from my test car. Loud enough to screw with my phones microphone lol

 

where do you tap the output from a base stereo without OEM subwoofer Thanks

Ed