I got this from Ebay for about $60. It is off a year 2000 Impreza 2.5RS so is the factory short shifter. It is about 3/4" shorter above the fulcrum (the bit with the knob on) but the same length below so is not as "short" a shifter a some of the after market ones.
Installation was fairly straight forward but I recommend not following the instructions in the Haynes manual as they will have you pulling out the whole assembly which is both unnecessary and a pain in the arse. Also, there are instructions for this on the AZScooby web site but they neglected to remove the circlip that holds the shifter in place and just tugged on the unit to get it out and used a hammer to get the new one in place! Argh!!! As I mentioned, there is a circlip that holds the ball in the socket. It is accessible from under the car and requires circlip pliers to remove and reinstall it. It's a bit of a tight squeeze as the drive shaft and exhaust are in the way but once you have removed it the shifter lifts out easily.
The shift did result in improve shifts but I think, in hind sight, that the after market shifters, with the longer shaft below the fulcrum, would be even better. There is also much talk on web pages about replace the shifter bushes which is very economical and easily done. I feel this would be beneficial also.
I also think it would be possible to simply modify the original shift lever. You would want to shorten the upper portion by about an inch and lengthen the lower portion by about 1/4" to 3/8". now I have a spare OEM shifter floating around I may try this one day.