i faced a simular situation, I had a all plexi glass sub with a kicker solobaric and it slid around in the trunk so i took it out and had a custom trunk done with two rockford fosgate 12's fireing back, the rest of the trunk was all did so that the amps are sunk (above the tire, a rockford 800.2 and 400.4) and the sides were done, left side houses the clarion cd changer, right side houses the rockford digital cap and behind a pannel that pops off is a hidden vcr. to the guy that says you can't hear it, it is true with the benz trunk they are harder, perhaps you need more amp or speaker or both. mine pounds my ears off. i can find the pics and upload them if you'd like? good luck