Andrew,
I only made a few cuts with the stock muffler, maybe, 10, but when I put the modded muffler on it, instantly throttle response (spool up time) was much faster, my little girl even new that, as she was videoing and she said "It sounds faster.", LOL.
I cookie cut with it, but didn't use big enough wood and the saw wasn't broken in so I probably won't post those videos, as it will cause a ruckus around here with no justification for it. My SS muffler doesn't even have any color marks on it as it didn't get used hard enough to get hot, before I changed it.
As to the small smilie (face cuts), I don't see the point in wasting that time on making them bigger if the tree had enough lean or weight to one side all you need is enough hing to not pinch your bar or give it a little direction, anymore and its just a waste of time, as a cutter is just double cutting the same wood for obviously zero gain of anything. Additionally, if for some reason I do split a tree which I have maybe done that 5 times in my life, and I can only really think of 3, I only slab some off the side, I don't really barber chair one down the middle and more or less ruin the whole log, slabbing the side is a minor loss of board footage and produces a wimpy barber chair, but if you cut a deep notch, you can barberchair things really bad and possibly lose your head/life over it, and the whole butt log is ruined.
Additionally, if you make a shallow hinge, like I do, if the tree is hollow, which in the flood damaged stuff it is, you are sure to be hingeing in solid wood not just the corners of a deep notch, so to me its a lot safer, too. I do deep notch them if I really, really need it to go in another direction and its straight enough up that I can use a little of the tree's trunk weight to help move it, but for the most part I can get them to go where I need them to go without a lot of fancy worded cuts, LOL.
Also, the shallow hinge will typically if not always being in better, stronger wood, it gives your hinge a lot more leverage or strength to hold the tree, if it wants to go the other way and you are going to push it over with a skidder, another tree or wedge it over (but it takes more wedges or you have to wedge from the side to get closer to the hinge for angle). Like in the below video I do a double and the 2nd tree is really leaning towards me, so here I want a shallow hinge to give the heavy leaner more strength to keep it from falling on me or breaking the hinge before its properly guided by the first tree.
I do have to adjust the top angle of the notch for the ash trees as they will blow up or slab if you don't give them enough angle to close before going over, but you can really cheat pin oak, soft maple and red oak ....................... Hickory, white oak and ash need more angle, closer to 90 degrees before they won't split or tear out on you.
Hope that makes sense, if I could draw pictures, I could explain it better, maybe I just say it in a video after I'm looking at a shallow hinged stump, because then it would make more sense as to why they are stronger from a leverage point of view. I think its obvious why they are stronger if there is hollow or rot to be dealt with, but a lot of people, even most loggers don't understand why its stronger from a leverage point of view, on some smaller diametered trees close to double the strength depending on how deep they hinge, but it might be more as I don't think the effect is linear, but more involute in nature.
Later,
Sam