I have a sealed box that had a kicker comp 12 in it, and now I want to replace it with a jl 12w6. The box was custom made for my car, so I want to keep it, but the internal airspace is 2624.54 cubic inches, 464 cubic inches bigger than jl's specs. This is after accounting for driver displacement. Is that enough to change the sound quality? Also, would it solve my problems if i just glued down a 7x7x7 block inside the box?