Well, I have done many researches for upgrading. I bought 6603 10spd Shifters, Sram 10spd cassette, 10 spd chain. However it doesn't work with 10spd XT M780 Rear Derailleur.
With proper wire cable installation; I still couldn't shift the RD to last two biggest teeth sprockets. I have searched couple post and people said Ultegra 6603 doesn't work with any RD with Dyna Sys...
Do you guys have any solution ?