Something that should be mentioned, but often isn't, at least to keep in mind for the chainsaw porting learning crowd, is that there is no free lunch- everything is a tradeoff or a compromise of something else.
More power is achieved at the expense of fuel economy. A saw can be ported for more torque to run a longer bar, but often at the detriment to peak RPM, which results is slower chain speed, which can make the saw actually slower in smaller wood with shorter bars. And inversely, a saw that becomes a "screamer" with more RPM in the cut for a given bar may be sacrificing torque in the lower RPM range that would be noticed if you are trying to run a longer bar or start a chain in the middle of a cut.
Tricks can be played for higher compression to squeeze out more power, opening exhaust restrictions, or adding bridge/finger ports to achieve better flow, but the engineers who designed these saws and engines probably knew a hell of a lot more than we do when we adjust their characteristics to make them "moar better" by grinding on them.
While these saws were designed to cover a broad range of use cases (long and short bars, soft and hard wood, operating conditions from high altitudes to sea level, etc) porting can sometimes make a saw perform better in specific cases, but not as well in others.
The only thing I think about is what compromises they made (such as for EPA emissions) when they designed these saws, and would overriding those choices make a better saw for me?
I tend to take a minimalist approach to augmenting the original design, but others have luck with more radical changes. I personally believe you begin chasing diminishing returns after a certain point.
Anyway, just something to throw out there to remind people of.
