I designed and built a box some years ago for 2 kicker 8's that fired downward (ported box), and fit entirely under where the top folds up. was approx. 3/4-1" off of the "floor" of the trunk. ports fired towards the back. basically looked like a trapezoid with the woofers pointing down and had "feet" keeping the bottom of box where speakers were mounted off the floor.
I wish I had some pictures of it as I have another 93 vert and want to do a similar box again. I may use a single Kicker L7 this time, or do another solobaric 12 in the spare tire well.
~~Project OMG RUKIDN ME?~~
built aod, 03 Mach I rims, Pony Down Stage 3 Kit,Tokico 5 way illumina's, Systemax upper/lower,indiglo gauges, Pa 130 amp alt., various phantom gauges, 331 B50 Block, Forged internals,TFS stage 2 heads/cam and 4 doors of FUN in a 79 Ford Fairmont