The main reason I do not like ESS stage one is it is does not have a cooler on it. The main reason this kit is $2,150 more is that it incorporates an air cooler in the form of air to water intercooler. I like that they are adding a front mount radiator/cooler just for the air/water cooler circuit, G-Power used engine coolant in thier kit (I think).
This kit will "come on" with better low end being air/water over air/air as it has less piping to charge. Running a stand alone cooling circuit for it will keep those air temps nice and managable and you can always co2 spray that radiator for a little extra. Something like a NOS pedal system that sprays/fogger the radiator under WOT only.
Would be a nice inbetween for someone that does not track their car alot and wants to retain a hope of traction =-)
Here is a better way to describe the "two heat exchangers". The air/water system has two water type radiators (aka heat exchangers) one located behind the front bumper, the other located inside the intake manifold. It has a self contained water/cooling circuit that moves water from one radiator to the other (absorbs/convects heat out of the intake air charge, dispells it with the front radiator, repeat). The air charge only runs from the output of the super charger directly into the intake manifold.
Here is a good link on air/air vs air/water...
http://www.enginebasics.com/Advanced...tercooler.html
Even though this kit heat soaks with extended track use it would be better to have some form of cooling over none at all (ESS S1).