Do you think the blue saw has more in it with a tune? The 372 and clone 660 sounded very safe kinda a long bar/stumping tune to me it could be the video too. Have you put a tach on them to see what they are actually running no load and in wood rpm? One thing ive noticed with aftermarket coils is the timing. I have some (10) for the 6xx jonnys that are very aggressive ie no retard for starting. I went back to oem to test and my recoil jerking was gone but so was alot of performance. Curious if you have noticed the same trends with the coils as i have.