I also upgraded my subwoofers to the SBA models. Ohm says the new subwoofers will go lower than the previous model. You probably will have to ship the orginal subwoofers to Ohm so they can rebuild them. I love these speakers and they still sound nice. The other speaker in my second system is the Proac 3.8 Response and the I's do a fine job for a lot cheaper price. My only complaint about the Ohm I's is that they sound bright. I did change the dome tweeter awhile back and they still sounded bright. Good luck.
Kevyo
Kevyo