i cut a hole in the wood floor in the trunk and made a box for my amp with a plexie glass on to see it. I also remove the spare tire and put stands in the bottom to support it. My amp is sitting flush to the floor so i can put stuff in my trunk still. I am not done it yet cause i need some carpet. I will post pics when i am done.

 

mines mounted to the box. asked around and the general answer I got about under the seats was they were more prone to overheating. It's really about what gear you use tho...some amps should definetly not be mounted to the box, as they will vibrate at levels that the shoddy manufacturing can't withstand.

 

Coming back up.