I think the PC is mounted on the other side of the 3 screen set-up. The website has higher res images and after zooming in on two of the images showing the back side of the seat....I'm stumped. Perhaps they are some type of tactile tranducers? Between the 4 metal boxes is a fifth with what appears to be a cooling fan. If they are transducers, this may be the amp for the units.

Great looking rig and I must say I would love to have one like it.
Derek