I have full range speakers back there now. The sound is better with setting the processor to limited for the rears and crossover @ 80hz.
The Incredarrays have 4 Peerless XLS 12" subs powered by a Crown K1 and Eq'd by a DBX DriveRack. The bass is already more then my house can handle. That is not just a figure of speach.... On movie tracks with deep bass the entire house and probably a few homes on each side of me are rattling like crazy. Windows banging, etc like a twister is coming.

No thank you to more bass. The 2 12's got it covered in my room.