The 25 has an angled plug that is on the side.The 22 has an angled plug but it has round cylinder like a glow engine.Check out this forum by putting mufflers in the search bar.Theres quite a bit of info on hommade ones.Especially by av8tor.We gut the stock ones and plug any outlets and then add a pipe.Also go to [indianatinygasengines] and look at his and he can weld and do a lot of things also.Tell him the guy that bought the3x 14cc echos sent ya.You should be able to get your motor done for 100.00 or less.[total].Keep posting and if ya need any help PM me also.If ya need an intake let me know and ill look and see what i have.Mufflers also.
Just went and checked,a muffler[stock] off of a G23-26 will bolt right on with no mods.I have a brand new zenoah pitts muffler off a G23,bolts right on,horizonhobby sells them i believe for 19.95.They also sell others for the same engine.