I don't think I agree with that - not just because I've ever tried using one of my old PSB alphas in the center and pairing it with a couple of floorstanding Klipsch's - but because something tells me that no matter what speakers you're comparing, some combinations will sound better than others...
Can't comment on how close a match the PSBs would be to the Paradigm's (they share much of the same pedigree so it's not beyond the realm of possibilities)...
But, if you're going to consider investing in new speakers, invest in a new front three and leave the surrounds alone. The...