Most people claim that a short shifter will wear out the syncros. I see no reason why. A true short shifter (i.e. it changes the throws by moving its pivot point, not just shortening the lever) shortens the distance needed for the shifter to move the shift linkage by increasing the amount of effort required. Maybe if a driver is more likely to drive like an idiot and bang out shifts all the damn time there would be some ill effects, but the linkage moves the exact same distance even though the throws of the shifter are changed. In a car with a longitudinally mounted transmission where the shifter is actually a part of the gearbox the only difference is that it's attatched to the shift fork itself instead of via a linkage. The same thing hapenns if you shorten the throws though, the shift fork moves exactly the same amount as with the stock shifter.