in my country we sometimes have 125-130 F heat....although its not fun driving with this much heat..its perfectly ok..and im having no problems

 

4.56 gears totally eliminated the "heat bog" problem I had with my '04 S2K. Even with the air conditioner on at full blast in southern Louisiana, the problem was eliminated.

 

Sorry, I have the 4.57 gears (now wishing I purchased the 4.56 set). Anyways, the 4.57 set eliminated the heat bog issue. If you're thinking about this upgrade, the 4.56 sounds like the way to go. The 4.57 harmonics are definitely loud when cruising at around 60-70 mph.