It is most likely the simplest mod you can do. And, as a bonus, I really don't think you can screw it up in any way.
I just ordered the Kartboy Forester-specific short shift from Kym at Aerosim Research. firstname.lastname@example.org
She has a batch on order and I think, other than Tom himself, is the only vendor that has the Forester SS.
Make sure you order the harder bushings too, they make a world of difference and are just as easy to install.
The only problem I had was getting the bolt out, and that was just an exercise in patience.