I noticed from some of your other posts we are running the exact same bike, big bore, ecu and kit. I'm looking at doing the CMX as well. Please report your findings. I added the 6 speed last year. It is great for making time on the trail. You likely have the same configuration I do. You will find that on the way up the trail, after about 6,000ft, when you are down on a little hp the gear will be a little too tall. I run 6th gear pinned all the way to 6000' and don't use it much after unless there are flat sections. The way down is 6th pinned all the way with a little help from good old gravity. A lot of guys hate riding the trail. It's not my favorite part of the day but as long as it isn't icy or too whooped out I have a blast. Especially rippn past the sleds that always say the bikes suck on the trail.