i have 2 sony xplods in a 4.25 cubed box (sealed) and yes thats big as h$$$ for 2 xplods in a 94 explorer running (A TRUE) 800 watts rms paralleled @ 2ohm and dude i have to say the sq is a little on the down side but it was d$$$ near the output of my 2 12w7 w/ the 1000/1. and yes the jl enclosure and amp setup is @ jl's recommendations.
i just wanted to play around a see how loud i could get the xplods without over doin them and sounding like s$$$.
oh by the way w/ the setup ive got they only hit the very low frequencys and is ok w/ the highs but a little sloppy from about 40-80hz.