I bought the bike with 9k miles on it. It now has 16k. I changed the rear tire about 1.5k miles ago. I just changed the front yesterday. WOW. I honestly didn't notice a difference when I changed the rear, but the front made the bike SO much easier to turn-in and to ride in general.

WoW. I switched from my Dunlop Qualifiers (stock) on the front, to a Pirelli Diablo. Wow.

Also noticed, my vibration went away after an oil-change. Went from semi-synthetic, to dyno, and feel less vibration. Odd.