One of the feature I'd like to know more about on the Ultra is it's (dedicated "sealed" mode).
Seems to me this would be a perfect sub for music and movies.
I wouldn't count on using that feature at all... you will lose a bunch of headroom, and its a ported sub.... Not a sealed sub... They claim you can seal it, but the data is out so far about performance in that mode so far... Or at least I would be using it...
If your spending that kind of money on a sub... get the ultra...
I have a plus/2 and a Plus in the same room, and they are great.... tons of bass, House Shaking to say the least... I was considering getting Dual Ultra 13's, but I am going to try my hand at DIY... with some really high quality drivers...
The New Ultra is stated to have roughly the same amount of output as the Plus/2 but sound quality is much better... Plus/2 may have a little more output above 30hz, but the Ultra 13 with have much better performance in the less then 30hz range and with subsonics...
SVS makes a phenomenal product... Fit and Finish are top notch.. as well as customer service...
Good luck on your choice.....