Yes the whole run from 2003-2010 there is a 'short' and a 'long' but you are probably seeing the mod that was popular a decade+ ago where they would...
Weight matters, but much, much, less in a torqu-ey bike. The fan weighs less than if you skipped breakfast, but since you've already gutted the crap...
Round 4 of CRA was rough. Crashed out of first (LAST LAP!) and popped the Tech 10 airbag suit. Fixed the bike and crashed out of the first race, 2nd...
Since you're holding the new axle, the answer is literally in your hands. It will be a VERY expensive tap to buy. Take a 6 pack to your local machine...