Marco i have had this problem with the sticky throttle. The garage i took it to did the cable mod and told me it was all fixed, but soon as i picked it up i knew it wasnt, but this cable mod did fix the throttle vibration.

Mine was only sticking if i went full throttle and then lifted off quickly and the next time i tried to press the throttle again it had stuck shut. They had to fit a new throttle body to cure my problem (all under warrenty)