Mostly agree, except to note that Polaris chaincase sleds have 3"x7t drivers, while the Doos have 3.5"x6t, so no real need to make any corrections comparing those two (2.31:1 vs 2.52:1), and same story with QD2. You're probably right that Doo changed gearing more for belt life than performance, but I haven't heard of anyone gearing back up, while a few people here have taken their Polaris chaincase sleds even lower, with positive reports. It probably depends a lot on the general conditions the rider sees, and elevation too; gearing is definitely not a one-size-fits-all proposition. QD2 is a step in the right direction and probably the ideal ratio for many riders, but still too high for others.