You need the TS parameters for the woofer to redesign the enclosure. Learn the tradeoffs involved in designs. I suspect that Klipsch did there homework and, considering the price point did there best to maximize performance.
But you are up against the wall of physics. One successful 'cheat' is Bob Carver who makes a line of fairly compact subs, but use very powerful amps. Just one of the available compromises.
David, Jan is referencing to a scene at the end of the remake of the movie he mentions where seth greene plays a set of Martin Logans and blows the clothes off of some girls.