I recently removed my rear heater also. Instead of the U shaped pipe, I chose
to simply plug off the two hoses and it works just fine. Someone on the list
cautioned me about the U. I even had considered utilizing the hoses for a
flushing tee of sorts. After studying the Bently, I couldn't see why it would
matter either way. The removal of the heater in any case is reversable, but I
like the extra storage under the seat.