I have a 2011 LTZ that I just added a sub woofer. I got a pioneer shallow mount 10” sub are used a two channel line output converter that I got from AutoZone for like 23 bucks. It’s wired to the two thicker speaker wires going to the small sub that came with the Bose system. I had to cut the sub box in length by about 3 inches. Sounds amazing! I have a 400 W Rockford Fosgate digital amp amazingly it all fit perfectly except for cutting the box.