I got my short shifter installed today at AA and here are my thoughts:
Stock M3 6MT transmission:
Overall, I like the transmission and enjoy the manual shifting. It always has been very smooth for me and like most, I felt the throws were too long. Additionally, i was surprised that the was some "slop" in the transmission. Although minor, it is present and i do notice. This "slop" is most noticeable when, for example you are in gear, depress the throttle, release the throttle, and then depress the throttle again- the transmission doesn't feel perfectly tight and the shifter vibrates a bit.
Active Autowerke short shifter:
short throw- It is advertised as 30% shorter throws and it sounds about right. Throws are noticeablely shorter and feel very precise. The height of the shifter is the same though.
"Slop"- I was surprised to find the "slop" was virtually gone or at the very least markedly improved. The system feels very tight and still extremely smooth.
knob- i stuck with the stock knob for now since I live in South Florida and the aluminum knob heats up pretty good. i think it is a personal preference, but i am happy with my choice so far.
AA facility- it was my 1st visit there ( i live like 20 min away), but I'm sure it won't be my last. There were a number of cars in the shop, noteabley a blk e92 m3 that was getting an exhaust/chip/springs installed. I must say, the exhaust sounds amazing- similiar to the youtube clip, but better of course IRL. The staff was friendly, knowlegdeable and helpful. There were about 8 car bays which were clean and organized- top notch as far as I say.
Overall- I think this short shifter is a must for 6MT owners, the precision is markedly improved as well as the throw distance. Although this is a brief review since I got it today (Tues), I am very pleased with this mod and will give an update in a few days.