Here's my theory. Those engineers are paid a ton of dollars to figure out how to make a saw run well...consistently even thru the manufacturing variances and discontinuities indigenous to the manufacturing process involving sub contractors and all the things related to parts & sub assemblies manufactured at multiple locations and finally assembled to a reliable running saw! :msp_scared:To think just hacking without a significant amount of knowledge gained either through research or practical experience will make significant gains is mythology.:msp_unsure: For the amateur to re-engineer that machine expecting to achieve both better performance over the life of the saw and reliability gains is a statistical game of luck.....so we make it cool here to hack and grind, some rev higher, some just get louder, and a few actually achieve the goals set out by the grinder in charge!:msp_w00t:
So...first. If you want to play this game, whether its you or you gamble on some one else, make certain you won't be too hurt if that saw never does what you want..it has to be expendable.:wink2:
Second. All the guys who will take your money to grind your saw have ethics. Some more than others. Make certain if they make a mistake and ruin a part, there is some type of reimbursement so you are not paying for their R&D and or mistake. IE you take all the risk they get all the financial gains with no risk.:msp_angry: (Unless you want to get into an R&D arrangement with that person and willingly eyes open take that risk)
Third. All the guys who do this for dollars have customers as references..find those who most represent what you are and do. (honestly) and take their experiences into account. If you can't identify your self...go with the professional loggers who put food on the table with their saws. BUT if your a working pro, the pro loggers are the best reference point, if your a cookie cutting GTG regular...take a look at the racing results for hints to who can build the ultimate cookie cutter. If you don't see the builder prominent in either world (logging pro's or racers) you are taking yet a larger leap of faith!:msp_rolleyes:
Forth...
If you want to do this yourself...its a LOT of fun, from a mechanical standpoint instant gratification at low cost when you get it right, and low cost / low risk when you get it wrong if its a saw not used for food on the table pursuits! 
(Verses Cars, Boats, Planes, Motorcycles, Quads, Snowmobiles etc...a CHEAP form of motorsport!)
Fifth. There are all kinds of threads with pictures showing the ways different folks do their port jobs..good place to get raw data and then compare to the theoretical data you find following the reading advice from the wise ones above. AND do the research as that will help wrap theory around what you see to help you build your own methodology on how to build a better mouse trap...for you.
Sixth. Better have a lot of room and a nice place to work because it can get addicting.
Seventh. To begin this game, pick a saw class that's financially accessible, has a source of parts still available, and is relatively easy to work on. For me its been the 60 thru 272 series of Husqvarna's..can ruin them and replace for very little money. Can have them down to the cases and back together in an hour or two. Lots of parts and even aftermarket parts to detail and finish the saws. Their maybe a Stihl counterpart, I just don't know what that would be.
That's my theory. I've wasted as much time and money as many..and plan to waste more!
(GTG's and race events are a great way to meet others, see how yours stack up and learn from your gains and mistakes!)
