The problem with short shifters:
The aftermarket wants you to believe that the solution to the problem is shifting faster. 'Short shifters' do this by decreasing the shift throw, allowing you to feel like you are shifting faster. In reality, the transmission regulates how fast you can shift, not the shifter. Shifting too fast causes synchro wear ('crunching' between shifts), and forcing the shifter into gear (easy to do on short shifters) bends or breaks the shift forks inside the transmission.
'Short shifters' are all shorter (height wise) than the stock shifter. While this may look 'cool' or give the illusion of 'performance', it is the furthest thing from the truth. The stock shifter is too far away from the steering wheel to provide proper shifting and steering techniques in the first place. So the worst thing to do is move the shifter even farther away from the steering wheel (with a shorter shifter).
Most all short shifters are made of aluminum. Aluminum is inexpensive and easy to manufacture, but it is soft and easily broken. There are many cases where even expensive short shifters from reputable companies shear off during shifts, in some cases causing over revving and engine damage. Check out the "big name" short shifter that sheared off at the threads below:
Steel is a better material due to its strength, and won't shear like aluminum short shifters. But steel short shifters still suffer the same basic design flaws as aluminum ones.
The other problem with aluminum is weight. Due to their lightness, aluminum short shifters transfer engine and transmission vibration directly to the driver. The stock shifter is made of steel, so its weight helps dampen the annoying vibrations and rattling expected with aluminum short shifters. A few steel short shifters are available, but again, all short shifters suffer the same basic design flaws.
Aluminum short shifters upset the counterbalance of the shift linkage. The shifter is connected to the transmission via the shift linkage, so when you shift you are moving both the shifter and the linkage. The stock shifter feels so smooth because its steel construction provides increased weight to counterbalance the weight of the linkage. Aluminum short shifters feel much worse because the weight balance of the shifter and the linkage has been upset. Shifting is now 'bottom-heavy' with a lighter shifter moving a heavier linkage.
Short shifters feel notchy, due to a combination of factors (weight, drastically shorter throw, etc). But another reason is the linkage bearings. Most short shifters use the same linkage bearings - metal 'roller blade' bearings that make shifts feel notchy and rough. Shift feel worsens as the bearings wear. The stock shifter uses rubber bushings that help dampen vibrations, but the rubber deforms easily and deteriorates quickly, making shifting very sloppy.
source:
http://www.fastlineperformance.com/shifter.htm