I did it with no problem at all. I just took it out very slowly hoping I wouldn't upset the spring and it slipped out fine. I have also been told that if it does fall you may be able to fish it out with a long skinny screwdriver. Good luck.
We know now that there is an early and late style shift arm inside the bike. My guess is the shift arm was changed around 04. If you have the later style it is almost impossible to get the shifter out of place. If you have an early style it is possible of the shifter to move far enough toward the front of the motor to allow the spring to come out of place and result in the bike not being able to stay in gear. Daniii had changed his once or twice already and gotten it done but a week ago Saturday apparently they tried at his house and the spring got out of place so this weekend we split his cases and installed new shift arm and updated his shift drum and shift forks to late style.
Floyd I use a pingle electric shifter and still have my original shaft in the bike. Dan's has been down a couple of times on the left side and I think he relates his failures to the bike being on the shifter.
So far, I know of no one that has had the shift shaft fail that has not replaced the left side frame rail within the previous year (if someone reads this who has not replaced the frame rail, and had a shift shaft fail, please advise us). I'm thinking that if you have to replace the rail, I'd be talking to the insurance agent about replacing the shaft under the claim. (In fact, I might be tempted to apply a hammer if I had an '03 or '02).