ORIGINAL: Ragz
I will prefer to keep it light and will prefer the 180rx as well. Just don't want an underpowered plane. I fly from an elevation of 300m with temps in the range of 35-45 Celsius.
Ragz,
My dad flies his with a 180 (kt) at 400m, 30 to 35 celsius, high humidity. He loves the performance on the 180.
Being at high altitude like you, I prefer to save on weight.