Dinqua's the expert, but I thought I would add this:
A lot of guys have switched needles, but whatever you do I would recommend getting a dyno run including fuel mixture measures before you start.
I had the TBS needles in when I went to get my dyno and it turns out I was WAY rich - I don't remember the ratio, but it was bad. The taper seems to have a lot more effect than a shim or two through a certain part of the throttle position range.
I ended up dropping back to stock needles and adding a shim - I did have better response w/ the TBS needles in but I would rather get another 6-8 MPG and be closer to the ideal mixture ratio.
NOTE 1: I think part of my problem is that I can't get enough air though the mod'd airbox and unifilter - I think that's my current bottleneck but don't want to spend the money for the Freak.
NOTE 2: Jacking w/ your carbs and air intake system is the probably the most time consuming and frustrating task you can do on this bike - there are a LOT of variables that come into play. Again, recommend putting some $ aside for dynos, and finding a good dyno technician and use his advice as a starting point before you jump into anything yourself. (the chart will tell the people who can help on this forum more than just what you feel or suspect)
