Has anyone attempted to pull the panels inside to install wiring for an aftermarket sub? Had this unit in my FJ cruiser and want to install in my new A3. I see a good amount of the back shelf is solid aluminum so I may invert it and hang the unit from there. Just wondering if there are any special areas to worry about for trim pulls. Also, if anyone knows a good existing pass thru on the firewall for 4 gauge power wire that would be awesome!

Thanks!
Jim