I really like my ICBM, bass is so much better now!
My final amp is 5 ch (FL+FR are biamped), so I'm 2 channels short, so I let my Marantz SR-8500 take care of the surrounds.
I feed all 5.1 preouts into the ICBM.
This means the ICBM cannot inject the output into the SR and SL channels (the Marantz has no FINAL-IN sockets), only into the subs.

Now I wonder, would it make a big difference in correct bass sound if things were ideal around here?
To tell you the truth, I borrowed an extra 2ch final to try, but it's not very easy to notice subleties I feel...