Try using a metal "L Bracket" to mount the subs. I mounted one side to the nearest metal in the trunk and the other to the sub enclosure. I mounted it on the side facing the rear seat, so you can't see it when looking into the trunk.
2006 GT, Strut Tower Brace, Gas Hood Struts, FR Intake Plenum cover, Metal Fuse Box cover, Moroso brake reservoir cover, Rear shock tower brace, Front Bumper Lip Spoiler, JVC DVD Head unit w/ back-up camera, satellite Radio and USB input, 2 - 12" sub-woofers, 4 - 6"x8" speakers, 2 - 6.5" speakers to replace the door subs, 3 amplifiers, LED lights under the hood and in the trunk, chrome e-handle on parking brake handle, chrome cup holder trim, and trunk lid cover with running pony emblem.
Last edited by huberoy123; 04-14-2014 at 10:45 AM.
Reason: Decided to add a photo.