I have a 99 KDX200. I run a FMF Gnarly torque pipe and Boyesen Reeds. I also live and ride primarily above 6500' elevation in north eastern AZ. Being in Colorado I asssume your riding is much like mine. Like the other responses, I have found first gear with the 12t front almost impractical. However, I can't count the number of times I found myself on a billy goat trail and it was perfect if not necessary. Second gear becomes excellent for lugging around and when things get really tight 1st is a god send. When I am riding in tight stuff with the 13t, the clutch gets used a lot, unlike with the 12t where it rides more like a big thumper. In the open stuff, stay with the 13t, it's a lot faster, and I'm not sure it's humanly possible to shift as fast as the 12t demands. Besides, it only takes a couple minutes to swap out and adjust the chain back. How much more versatile can the little Kawi be??? Enjoy...