Mach460 rear speaker enclosure??

I am setting up an amp rack in the trunk.
Question is, if I replace my rear deck speakers do I need to keep that big plastic cover that is in the trunk covering the rear deck speakers. Its in the way of my amps.
I assume it acts as a "box" to get more base out of the rear Mach460 speakers. I will be replacing with Infinity Kappa's probably
The cover has to go, any ideas??