I don't think you should replace them. The whole idea of this test is to find out what kind of use you can get out of the stock bike. Throw on Sora's and your $150 bike is now $280. I would have bought a Kona Smoke for that. Even the $219 K2 Zed Sport I bought on vacation shifted perfectly after a week and ~130 miles (both on and off road).

Seriously, I say leave it stock and deal with a little sloppy shifting. I'm really intrigued: can a commuter get their money's worth out of the Denali?