Gameover isn't the best of examples to prove the point. He has some other mods that haven't fully been vetted out and tuned in completely.
Let'* use my 97SSEi as an example. I used a gutted airbox with K&N filter. Cut the radiator support to match the box opening and sealed it up with some weather strip foam. Added a high flow cat, ported exhaust manifolds and a 3.4 pulley. KR was very minimal in the summer at full operating temps and high humidity.
Many things factor in.. including altitude, humidity etc etc. While the supporting mods do wonders for helping out, everything needs to be considered.
00 Regal GS: All kinds of cool stuff.