2003 SSEi did this on his 93 Bonneville. Had to max out the torque bar to hold the lid up and when it would be shut..you could loose anything that was laying in the path. It makes a lid very heavy overall.

I mounted the amp up under the rear deck like 800 did. Works great, looks great when you bend over and see it, out of the way, less wiring and it's fixed. There's no potential for it to be coming loose when the lid is constantly closed.