A jet kit is only a waste of money if your quad performs at its peak stock. Many quads are not jetted properly from the factory cause they have no way of knowing where you are gonna be ridding it. Many climate of elevation factors can make a stock quad run less than perfect. You have to be able to fix what they didn't when you pick up your quad. For me that included a jet kit, adjusting the shocks, and bringing the idle adjust up a little. If your jet kit didn't help then you may want to switch back to stock. I can only speak from my experiance. I have sold bikes cause they ran like $hit when it probably only needed to be rejeted.