I just purchased a brand new RSW-15 and have found it to be a great match to my Khorns. I previously have used an SVS 20-39 pc+. Although the RSW-15 is great with music and the Khorns, I have found it cannot keep up with the SVS when it comes to movie sound effects. So.....it will be a challange to pick the right sub for your application.
Parasound HALO A52, A23 amplification, Integra DHC 9.9 Pre/Pro, Panasonic BD-55 Blu Ray. Mains - Khorns W/ALK crossovers, Trachorns with JBL 2470 drivers, Eminence APT-150 tweeters, Center - La Scala W/ALK , Trachorn, JBL mid & APT-150, Side Effects - 4 Cornwalls, Sub - SVS 20-39 PC+ for movies and RSW-15 for music. 7.1 setup. Projector - Sharp Z12000, Dalite HP screen. HTPC for lossles .flac audio. My gear at: http://www.prontoweb.com/klipsch_HT.htm