"How would this beast compare to the Marty Sub?"
this is kind of like dual marty subs in a single enclosure, BUT the enclosure is a little smaller so the low end sensitivity is a little less, but just a little. the other difference is the ports. this version employs round ports that are smaller than the slot in the marty sub. port velocity will be higher, so chuffing and compression may set in a little earlier, but it should still be ok, more or less.