I custom made some behind the grill 20" light bar mounts for 2014-2016 models. I decided to have extra sets cut out, hoping to help out some fellow members that need a quality way to mount a light bar behind the grill. The mounts are 100% water jet cut, tig welded, 6061 aluminum. They bolt directly to the aluminum crossmember behind the lower portion of the bumper by drilling and tapping (4) 1/4-20 holes in the aluminum X-member.
If you need a set shoot me a PM, price is set to recoup the costs of material, water jetting, and weld time. I can assure you won't find a better behind the grill mounting solution for a better price.
Picture of my light bar mounted with these mounts below.