started with my first "real" sub as the svs pb10nsd. enjoyed that for many years and thought it was fantastic. ran across an article about PSA and how the owner was Tom V. and became interested. noticed they had 15's and became very interested in replacing my very capable pb10. temptation got the better of me and next thing you know i had an xv15 ordered. got it, and soon after sold the pb10...was absolutely floored by the capability of the xv15. loved it. kept hearing about the love for duals...swore i would never need duals as i was very happy with the single xv. again, gave in to temptation and wanted to see what all this dual talk was about. long story moderately short, there is a big difference between a single and duals and can't imagine going back. so, i know you SAY you only need one sub, but eventually you will find yourself creating a space for a second sub and you will realize how smooth and powerful it is...no matter where you are in the room. great stuff. btw, also had a friend that was there when i dialed in the single xv....called me crazy when i got the dual xv....he came over to see the difference...he doesn't call me crazy anymore. he calls himself envious.
and to weigh in on the balanced inputs...no need. i have one running off a 6' sub cable, the other on a 20' cable run through the basement. my receiver only has single sub input, so figure a y splitter in there too. no hum, no distortion, no nothing. don't sweat the fact there aren't balanced inputs....just plug and go!