Besides pricing, (1) I see that one has 4 hoses (hydraboost) the other one 3 (2) the hoses connect on top on hydarboost the other from the bottom, (looks like the unit is reversed), anything else.
the hydratech setup probably just uses a later model booster. from the pics i've seen, they look like the booster in my 92 Astro. they probably just use the cheapest booster they can find that can be easily adapted to a number of vehicles.
