Sorry it took a long time to get on the thread.
Our experience is that heat does play a part in the equation, but the heat portion of the equation is dwarfed by the importance of the shape of the turbine housing.
The physics can be debated back and forth, but for customers it comes down to dyno numbers, track times and how much money/effort it took to get there.
The people who hate our system generally have never ridden in one of our vehicles.
Here's a link to videos of some of our faster customers. We hope that in the next couple of weeks, we'll have a customer with a GTO in the 9s.
http://www.ststurbo.com/fast_customers
Ben