These seem almost too good to be true.
A high efficiency 316SS 55k BTU heat exchanger for $149?!?
Yes, Tri Clamp connectors for the wort-side would be much better than NPT, BUT...
Why can't this be used as an awesome counter flow heat exchanger for HERMS brewing and wort chilling?
(Or even an external boil kettle calandria if low pressure steam heat is used?)
These are a full $50 cheaper than copper convoluted counterflow heat exchangers with far more heat transfer potential.
Example: http://www.ebay.com/itm/Outdoor-Wood-Furnace-Boiler-Stainless-Steel-Pool-Heat-Exchanger-55K-BTU-/151037565985?pt=LH_DefaultDomain_0&hash=item232a8a 5c21