I did the HG on my M102 about 1.5 years ago. Wasn't too hard, but yes the head is heavy. It's difficult to get in the correct position for heavy lifting. I remeber I climbed on the strut towers or something. If you do this, remember that you'll have to get down with the head in your hands... Definetly do the stem seals again since they are so cheap and you'll have to remove them when cleaning/machining the head.