I don't suppose theres a German Chick & a Sweedish Chick with a small screw driver that are revving new saws listening for the " 4 Stroke" sound. Do they use a Maf and an o2 sensor to adjust then pop the limiter caps into the middle position. if a person had a spare muffler it would be possible to tune with an o2 to be sure the rippin "By Ear" tune is indeed a good tune. Some times I wonder how good my tune is and the spark plug doesn't tell immediatly. But an o2 would. I have an air/fuel ratio meter in my supercharged silverado and it wouldn't be a big deal to install it into a saw muffler. Any Benefit?????????