Def Tech BPX vs. BP2X

[tippykitten]

Hey all. I'm looking to invest in some surround speakers here very soon. I am currently trying to decide between the BPX and the BP2X's.
I already have my fronts (BP6B) and center (CLR-2002). For the AVR, I'm currently looking at the Pio Elite SC-07 (which provides 140 WPC). I'm curious as to how much different performance-wise these different speakers would be given the rest of my setup.
Also wondering if based on the difference between the two, would it be worth it due to the cost difference ($260ish each for BP2X and $500 each for BPX). I'm also planning on going 7.1 as my room is quite large. Size is not as big of an issue as they are fairly close in size.