Nick, your premise about the bigger sub sounding "sloppy" higher up compared with a smaller sub doesn't really have factual support. As the info linked by Dr. Horse indicates, subs operate at very low frequencies which are inherently "slow". Forget about those frequencies being "quick", "tight", "musical" or similar qualities. Set your sub for a crossover around 60Hz and listen to some bass-heavy music with the other speakers disconnected to get an idea of what the bass alone really sounds like. Any "quickness" in the sound from a bass instrument is due to the upper harmonics which the speakers, not the sub, play.
_________________________
-----------------------------------

Enjoy the music, not the equipment.