That's Ron Maximoff. His first setup had a A frame type bar above the center of the Axle. There was only one place it mounted to the axle and he broke it a few times. Now I think he has 2 upper bars, still at the A frame type angle. I havn't heard of him having problems with it since.
Also the pad just behind the spring mount is there for ride hieght adjusment. The springs sit on it at rest. That's about all I can think of for now. I never built one, but I ran with him a few times on the trals fter he did it.