I don't know if the thermal efficiency of the KB blower is up to par with that of the better centrifugals out there (how much heat the blower adds to the air when compressing it). I know I heard Tim mentioning high inlet temps on some KB cars. I know for certain that roots cars like my own make all sorts of intake heat in the high rpms. The air to water coolers also tend to heat soak after extended hard runs. It is not so easy to get the heat out of the water into the atmospheric air after it was taken out of the intake air charge.
With any forced induction, when you compress air the temp goes up. The air to air and air to water coolers take some of the heat back out before the air enters the cylinders, though. Usually you'll hear people refer to pulleying down their blower after installing an air to air cooler on a centrifugal car, to get back boost lost in the cooler. Cooling the air will drop the pressure, but the cooler will also restrict airflow more. You need to turn the blower faster to make up the airflow loss, but the cooler air allows more timing and shorter cool downs between track runs. Also on a hot day, the cooler will help to prevent engine damaging detonation or preignition. Many 03 Cobra owners are changing the heat exchanger for the blower cooler under the front bumper to a larger unit. This allows their air cooling system to hold more fluid and dissipate the heat more rapidly.
-Jason