Sploke, the plan is to put the power head filters on them, just have not gotten the chance to pick them up as of yet.
H3D, the flow into a regular HOB is one sided. With this set up the out flow hits the front glass splits as it is split it is drawn into the far corners of the tank. Instead of haveing to cross the flow to get back into the intake.
Fish, the extra elbow is for suport of the filter. The filter is made for bigger tanks so the top frame of the tank is not as big.