I'll take this one,
I have run the KC with my HE blocked on the street and highway, and the performance is quite incredible, specifically IC fluid temps in the area of 50-60* on a 90* day while cruising down the highway.
On the road course I run with the HE uncovered, but I also run a stock HE.
The KC is also a much safer mod to run on the truck than the icey res when it comes to AC compressor life.
I read somewhere about having to change the AC charge. I'm a bit of a noob when it comes to AC systems, I just know that the ones on these trucks are freaking over powered for the size cab we have. Is there anything particular to note about refridgerants and the relationship to IC temps and how COLD cold your A/C will still operate at when you actually want it to be cold in the cab?