if your going to do all this why not get an overflow box ( i prefer www.glass-holes.com
) and drill the back of the tank. pick up a cheap used tank, say a 20 long and use that as your sump. you then can fill this with bio-balls, filter media, your heaters, whatever you wish.
( for anyone reading along, a saltwater sump should not contain bio-balls or filter media )
personally i just find doing this cleaner and easier and honestly prob. cheaper then both those fluvals. im not familiar with a UGJ? i know UG is under gravel and if this is what you mean, i would not use this method in my tank. sorry, i cant help you with the cichlids and fast moving water, ive always kept softwater and saltwater fish. hope this helps some, welcome to the forum.