Here is a good article on octane and why you should run premium when the manual recommends it.
http://www.superchargersonline.com/content.asp?ID=105
The 3.0l engines have a 10.2:1 CR and the 4.4's have a 10:1
Not sure if the heads and block are Aluminum? Anyone know?
MotorDave: "I think" that at your elevation you can get away without using premium. However I am not sure. Maybe someone in the mile high city can tell us.
Jes