I can "second the motion" that the stage 1 is a waste of time and money. My bike came to me with stock headers, Holeshot slip-ons, and a DJ stage 1 kit installed.
It ran OK, but the midrange was soft and not very responsive. I ended up putting the PAJ2's back to stock, and switching the mains(found 150's in there) to Sean's suggestion of 147.5's. The stage 1 needles are OK, the adjustability is what you want. I have mine on the 4th clip from the pointy end.
Runs good. Switching the mains down a step maybe seemed to crispen up throttle response in the v-boost zone, and the midrange is perkier than it used to be as well.
Slip-ons don't add any power(any that claim to are BSing you). The benefit is just a cool sound, and you can save a few lbs since the stock muffler is a total brick.