If you can find a replacement 9 speed Ultegra shifter, I suspect that the "6510" might be slightly better than the original "6500" shifter. I bought a new old stock 6500 9speed integrated brake/shift lever a few years back for about $60. It does shift fine but the engineering was a bit less refined than the Dura Ace 7700 one I was replacing. There did not appear to be sufficient bump stops in the lever and the lever would vibrate metal on metal when hitting expansion joints on bridges or navigating broken pavement. My Dura Ace 7700's seem to have some internal rubber bung to mute this.