i got metal ones in mine and i love them
highly suggested

 

metal bushings would not increase synchro wears but a short shifter will. a short shifter will make shifting faster, which forces the synchro to work faster because it's forced together faster creating more heat and wear.

shifting slower with a short shifter defeats the purpose of installing one to begin with but i guess to save your synchros, use it only when at the track and shift slower for daily driving.