Some models require a timing advance, some don't. Some require extensive muffler modification, some do not. Some builders like to change coils on some models... what one builder does is not a given rule. At this point most are using a lathe to cut the bottom of the cylinder, the inside top of the cylinder, and then moving the ports to match characteristics they are shooting for. (Think changing a cam in a automotive engine.) Not all models need these changes. Some builders like to "spin a pop-up" or a raised bump on the middle of the piston as opposed to cutting the "squish band" inside the cylinder. There are LOTS of variables.
IF you are looking to find someone to port your saw, ask several. Talk to them and have it detailed what they like to do to that model. Ask if they have done that model before and ask for their thoughts. Find someone you are comfortable with and go from there.
What I think is often misrepresented is people want a ported saw to run more bar length than designed. Sometimes this can be done but not always. I have a ported 372. It still wears a 24" bar. It runs that bar better than stock. Yes it can run a 28" or 32".. but the chassis in my opinion isn't really suited for that day in and day out. Porting simply makes a saw do what it was intended to do better. Most of the time you will see snappier throttle response, higher RPM while under load, and most of the time more torque allowing you to push on it a bit more. Porting will not ever make a 50cc saw a 60cc saw. Porting will band-aid poor chain maintenance. Porting will not make all of your cuts line up and trees always go the way you want.
