I did contact SVS, they no longer offer amps for the passive subs. They recommend Samson, which are quite expensive here in Canada.
The Behringer model you mention I have also looked into, same price range here, between $350-400 CDN. and does not have the "sub" controls the PSB has.
This PSB amp sounds good, but I am waiting to hear from PSB in regards to the load at 4 ohms, the specs are scarce on the website to say the least.
They advertise this as an "in-wall" sub amp, could this possibly make a difference?