Best upgrade? The rider: - Lose some weight - Improve your power output - Improve your endurance - Improve your mobility - Improve your skills (pick 1-2 during this downtime and see how you can focus on them. - Learn more about your bike - experiment with different tyre pressures, suspension pressures and settings, more sag, less sag etc. As mentioned above, try a slightly different saddle position (nose down, a couple of mm forward etc) I know that the greatest thing holding back my riding is me!