Originally Posted by Modshack

Syncronizers need time to spin up the next gear for a grindless shift. A short shifter, shifted at the same speed as before tends to rush that. I've had several short shifters on Porsche's without issue, but I'm not a speed shifter either. If you do it for feel, rather than for a quick shift you'll have no issues. Unfortunately changing the fulcum ratio (as most shrot shifters do) may make the "feel" unusually notchy and increase the shifting effort.. Porsche's typically have a relatively long throw so they're not affected as dramatically as some cars.