A bone stock 48mm version with gasket delete and .020 squish alone will surprise you if you haven't had the pleasure of running one yet. Very desirable saws in many circles.
Several notable design changes in them over the years. Mufflers/fitment (due to cylinder/exhaust port differences) is a major one as is the needle cage/clutch drum size. They're infamous for the difficulty involved with installing Stihl's rigid line onto/from the oil pump to the bar mount. One of the best 60cc class offerings out there, imho..., and I have a 262xp and a MS361 for comparison.