Sotsugyou M Manga
There are two distinct runs of Sotsugyou M Manga. The reasons for this are unclear. It's true that different manga-ka illustrated each set, which may have been part of the reason. However, my own theory is that originally the M/EMU project was intended to end in 1997. This is supported by the release of an E.M.U memorial book in 1997 (you don't release a memorial unless you're done recording, right?)
Yet for some reason - perhaps fan popularity - the series continued beyond that point with new drama CDs, manga, etc under the name of Sotsugyou M "plus". It seems probable that the original manga-ka was engaged in other projects at this juncture, and so a new manga-ka was found to continue the boys' stories.
Original Run: 1996-7
Manga-ka: Sugisaki Yukiru (of D.N. Angel fame)
The original run of manga begins with Takagi's arrival at the school as a transfer student, and basically introduces us to all of the boys and the odd world in which they apparently live. The opening volume and chapter is named after the first E.M.U single release "Bokutachi no Kotae", and occasional E.M.U references appear in the text (such as class members called Okiayu, Ishikawa, etc). The original volumes do not include characters such as Kusanagi Mizuho, the school council president - and the interpretations of Nakamoto's relationship with his stepmother and Arai's reunion with his old friend Kawazoe Haruka are different from in the plus volumes and drama Cds. The series ends with volume five which covers roughly the same plot as the second Makasero drama CD. It concludes the plot - but not really the boys' overall story. There is also no reference to "M" as a band in these volumes, although Takagi's musical past is covered.
The original run of manga seems to begin by following their adventures in the second year of High School, which corroborates the Drama CDs (in which Takagi joined the school at the start of the second year).
Plus Run: 1998-9
Manga-ka: Nishiomi Kyouko
The plus volumes begin somewhere in the boys' third year and from that perspective they can be seen as a continuity. However they tie in more with the drama CDs, and certain scenes are rewritten or given new angles to fit in with this development of plot. Kusanagi Mizuho and his coterie are introduced in this manga series (although already having been introduced in the Drama CDs). M as a band appear in these books (albeit briefly), and at least three actually released songs are referenced (two of which are credited to Takagi Shimon as being the writer, even on CD inlays!). The series ends with the boys' graduation, effectively concluding the plot and giving clues as to the boys' future plans. These four books delve a bit more deeply into the boys' individual characters and situations, which makes me like them better :)
To the left of this page are links to summaries of all the chapters, volume by volume. Some I've also done translations on - although the older the translation, the more likely it is to have errors (disclaimer is that I'm studying Japanese, I'm not fluent!).
I probably won't get round to translating all of the chapters - however if you specially want one done, you can always email me and ask. If I like the chapter, I'm more likely to do it (so basically, if it involves Nakamoto, you're probably pretty safe to get a result...heh).
There are also a few scans - although I won't be doing full scanlations because I can't scan fully without damaging the spines of my books. They were hard to get a hold of, so I'm not willing to go that far! However odd bits and pieces have been done, just to give an idea of what it's like...