My writeup after I installed the
997 short shifter is at
http://www.renntech.org/forums/index.php?showtopic=7371&hl= I am still happy with it after 2+ years and have had zero problems.
When I installed the 997 short shifter in my '01 Boxster, I didn't measure the side-to-side difference, just the forward-backward (I measured about 25% front to back reduction). I would expect the side-to-side difference would be about the same, since the pivot point moved to the same point. I don't notice much side-to-side slop.
See
http://www.carnewal-europe.com/cpx_p96139.htm for an ad with picture