Hi Mark, yes, it is very cool in the upper elevations, however the type of road you are on and the lack of air can give you an overheat situation. On the BMW GS twins you will appreciate the higher octane to avoid the pinking under load on the sand and dirt/rock roads. Many of these stretches are first gear.
I put the post into the Mexico route planning thread, thanks for the suggestion. I guess another thread in the Latin America section might not hurt.