Nice Dyn/Sim setup!
I just recently purchased the S5.4 with the Sim I-7 and Supernova. They're still breaking in, but sound amazing.
I noticed that you put the grills behind the speaker. Is that just a place to hide them or are you using them as sound treatment? I'm assuming that you live in Korea by the looks of the room and I believe that they use concrete for all walls in the apartments.

