Alright.. maybe my original post was a bit unclear thus I should clear up the question.
The short-throw kit will NOT directly damage the transmission or its components.
However, the shorter shift-time might lead to the following:
For example:
you are traveling on 2nd gear 30mph@4000rpm
change to 3rd gear at 30mph the engine speed should drop to 3000rpm thus you depress the clutch at 3000rpm
With the OEM gear throw, let says it takes 0.5s
Now you have the short-throw...
traveling on 2nd gear 30mph@4000rpm,
up-shift to 3rd... takes only 0.2s
engine speed has only drop to 3500rpm, which is not the engine speed for 3rd at 30mph....
either you depress the clutch thus you engage the clutch too early....
or you hold the clutch til the engine speed drop to 3000rpm.
^ those are the side effect I am talking about.
I hope it does make sense to you guys....
but correct me if I am wrong