M2 「M3いけませんでしたコンピ」 (M2 "M3 Ikemasen Deshita Comp") is a compilation album by yojomaestro. It is their 8th album. It contains 9 tracks, sung by Hatsune Miku, Kagamine Rin and Kagamine Len.
The official album website is available here. A crossfade of the album can be heard here as well.
The album is free to download.
Note: Only tracks 5 and 6 are sung by VOCALOIDs. The rest are instrumentals.