I wouldn't think ST would have an issue with the HP quoted herein, but with the weight. There is no way the MS261 weighs 11.9 lbs - 2 ounces more than a 346XP NE. I was issued a 261 for work and given the option of using that with a 16" bar or a 341. I thot they weighed close enough it didn't matter, and I used the 341 instead. They both handled like dogs, btw. I eventually replaced them with a lightly ported Echo cs-520. My guess is that 261 weighs closer to 12.5lbs, which puts it at about 7 ounces shy of an MS361. Unported, they are sluggish on throttle - exactly what you don't want out of a 50cc saw. The new m-tronic better fix that.