Near hundred degree weather will definitely damper your times if you don't run a cooler. Even with some form of a cooler, the higher ambient air temps (near 100) will produce less power than if you were running at 85 degrees.
I started out with 2 smallish IC's on my modded twin turbo S4 and made great power. I eventually went with a single large FMIC and lowered my IAT by 11% and performance obviously improved. Regardless of this, a 10 degree swing in ambient temperature had an equally significant impact on both setups due to the heat as timing retarded. I know they are different cars with different setups but the principles are the same.
So even if you had the water cooled heat exchanger, you would still see a relative drop in performance as the temps climbed. The 5 - 10 degree difference is definitely enough to be felt and measured.
Would it be enough to negate the benefit of having the blower in the first place? On a very hot day, I think it's very possible. Especially when you consider the parasitic nature of superchargers.
All that said - I'm still going to SC my car. Just going to have to lower my expectations when it's hot out, but then again...I'm used to it.
Thanks for sharing!