Hmmm, well, I have a factory pro jet kit here and they say that I don't have to drill the slide. I have read other jet kit instructions(dyno jet, cobra) where they say that drilling the slide is optional. I guess it is trial & error. I am going to try the new kit with no drilling, if I am happy I will leave it that way... if not then will be drilling and will let ya know how it goes. Let us know what you do and if it works or not.
The bike doesn't make the man, it's the man that makes the bike.