ive recently got an rs turbo which has got a lockwood white turned yellow dial kit fitted, its allways stuck a little bit so i dismantled it and pulled the needle out a bit so it didnt catch, i didnt take it off though. ive allways noticed that the speedo seemed out so i tested it today and wen my bro was driving side by side mine read 20mph and he was doing 30mph its the same all the time.

so how do i fix this apart from driving at 10mph less all the time?