Recommendations for improving visceral impact?

Hi!  I recently upgraded the majority of components in my system, and am happy with how it's going. I'm very happy with the detail, musicality, and separation of instruments. However, I think it's still lacking in visceral impact and also (particularly in two-channel listening) spatial imaging (both left/right and depth).

Our primary use is home theater - so improving impact is more important to me than improving imaging. 

Here's my setup - would love any recommendations for ways to improve... 

• Left & Right: B&W 803S
• Center: B&W Nautilus HTM1
• Rears: B&W 301
• Sub: Monoprice 10" Monolith
• Preamp: Marantz AV8802A (with upgraded fuse)
• Amp: Rotel RMB-1585
• Amp/Preamp Interconnects: Bluejeans RCA

The room is approximately 18' deep by 20' wide. I've added GIK acoustic panels around the room, as much as possible based on room layout and aesthetics. 

Unfortunately the couch is against the wall, which I'm guessing isn't helping... but there's no other option for placement. I've also tinkered with speaker placement as much as possible; the B&W's like to be quite far apart, and I'm maxed out on width at this point.

I'm using the Audyssey room correction -- it's necessary since the front left speaker is a few inches from the left side wall and a corner, and is incredibly boomy without it.

I'd prefer not to change out any components at this point, so my thinking is that the interconnects between the Marantz and the Rotel, and perhaps from changing power cords and/or adding a power conditioner, could be the way to improve here.

Thoughts or suggestions? Thanks!