Had one on previous cars and will probably get one for the Audi - just a bit busy at the moment! (It will happen along with a 60bhp power upgrade and better suspension!)
Its a doddle to do if you are reasonable competant at DIY mechanics. Its a little more than shortening the gear stick the center pivot needs to be moved to get the shorter throw. A Short gearstick will just make the long gear change stiffer. Most kits accept the standard knob so get the kit for your car and bung on the current knob.