I absolutely agree,all they really need to do is do some computer calculations based on inlet size and carb sizing,exhaust volume.....I am sure a simple twist of the exhaust flow will make a difference.When I was younger I worked for a motorcycle dealer and they gave me a Kawasaki KX 125 they got in trade for next to nothing and handed me a factory race prep manual and said"have at it!" I was instructed to cut and re weld the factory exhaust and exspansion chamber(the front bulge of the exhaust header) a certain way , rerouting the exhaust flow and man let me tell you that thing ran meen as hell!!! I could not believe it,but it did also give carb jet sizes to use.Our walbro have that built in simple needle settings do make a difference...............just a thought.