I would go for two of the same. The 2000 and 1000 are totally different in capability, and tuning. That means integration will take a great deal of time and frustration. Since the tunings are different, they will tend to cancel each other more than compliment, and on top of that, the pb1000 can’t even get close to the same output or extension.
I’ve seen this same question before answered by Ed Mullen.(technical director at SVS) Give him a shout.
edmullen@svsound.com (I think that’s right). He’s very friendly and knowledgeable, and is very quick to help forum members.