Finally got around to pulling the stock sub enclosure and getting some rough calculations. The subwoofer cutout is 7 3/16" and allows for 3" of depth without any modifications. I also painstakingly tried to get a rough volume. Due to the shape and pockets, one would have to seal up the speaker hole and slowly fill it from the small hole in the back to get more accurate than I did with my 2 part process. I filled from the speaker hole until running over, drained, then filled again with the box face down to try and get an idea of the volume forward of the woofer. Surprisingly, it held roughly 16 liters of water. Didn't fill I need to go any further with the experiment since the assumed 0.5-.55 cubic feet is plenty of volume for most 8" subwoofers. Seems Honda could have easily squeezed a 10" in there and satisfied all but the most serious bass head. Now to figure out what I want to do back there and probably return this Kicker 8" to Crutchfield.