I should be able to help.
Recently (a week ago) I purchased a 25-31PCi mainly for HT purposes. As you surmised, it is AMAZING for HT. Plopped LOTR into the DVD player and the hairs on the back of my neck were standing at attention. 12" driver and 325 watt amplifier. Very impressive. Very clean. And this is the 'runt' of the powered cylinder line at 32" tall and 16" in diameter.
For music, I ran RCA interconnects from my Plinius 8100's preouts straight to the SVS. Turned the crossover down to about 50hz which seems to match my JMlab Cobalt 816's. Have been working at calibration using Stereophile's Test CD which has a nice frequency sweep. Lots of trial and error required.
Conclusion: the SVS is a very powerful piece of equipment that excels for HT but works well for music. I'm still tweaking the gain setting (currently down to about 25%) but I've been very pleased with the results. For example, the complicated drum line and bass guitar on Zenyatta Mandatta (Police) now sounds amazing. Very tight. The SVS sounds like it's barely breaking a sweat. No plans to return the unit; I'm a happy camper.
SVS has a 45-day return policy so I'd recommend an audition/comparison. You could email their tech support with any detailed questions ... I did and the company founder got right back to me.