Brandon and Vespalad,
Here's a good one. I have two Grandes sitting here. One has the 49 jet in it and the 6 hole airbox and it runs like a champ. The other has the same 49 jet, but has the standard 3 hole airbox and it leans out and 4 strokes. I can't seem to figure out why. Fuel line runs free and clear, carb and jet are clean. I'm stumped. Regarding the performance pipe, let us know what you find. I have a Sito knock-off on mine. It is pretty loud, but added 6 mph to my top end. I'm still running the normal jet (49), but am considering playing with it by putting a 50 in that I have laying around. I'll report back after I get a chance to try.