Sub box fitment behind my seat on 08 F250 (bought used box from an 03)

[Biggredd]

I bought a used sub box from a guy recently that had his behind the seat of his 03 crew cab. Mine is an 08. He had car toys custom build the box so I figured it would fit just fine behind my seat with a little trimming. The box is 37" wide and when I start measuring for test fitment it looks like I have about 34.5" of comfortable room. Any wider and it looks like the center seat belt tower thing bolted to the back wall starts getting in the way. Is that trimable or movable or do I have options? Or should I frankenstein the box a little bit to fit better. The height seems ok and the depth I'm sure will be ok, just don't know about that width. Have a MTX 600 watt amp I'll be using and will probably put a 10" rockford fosgate shallow sub in it.