I'm the second guy linked above...lol
I have 2 max flo 2000 pumps running without the cage. I'm running tetra pond boxes. The plumbing was a tad tricky but it is do able. Just take you connectors to Home Depot and try different things until the work. I have even seen them plumbed for external usage and they still operate perfectly. If you have any specific questions ask away and feel fre to pm me.
Josh