A little late, but was unable to post for a few days. Anyway, while I was rebuilding my 051 I went and picked up an MS360. After tweaking the muffler on it I was quite pleased with it. That is until I saw and handled the MS361 for the first time several months ago. I looked at the differences between the two and then traded in the 360 for the new one. After working over the muffler I was amazed at the difference in performance. The 361 ran circles around the 360. It had more low end power and higher rpm's. The anti-vibe was redesigned for the 361 and it also has an improved ignition system.
I have put quite a few hours on it over the last few months and it still amazes me. In any event you won't be disappointed should you choose to get one.