From my readings (BITOG, rumor gas spec. test, M1s marketing, and oil technology) here's my best guess on the M1 product (these opinions are worth the paper they're written on) -
M1 0w20 - all Grp IV
M1 5w20,5w30,10w30 - no idea
M1 0w30 - all Grp IV
M1 0w40 - all Grp IV
M1 EP line - Grp III and IV mix.
M1 HM - Grp III and IV mix.
M1 0w20 - all Grp IV
M1 5w20,5w30,10w30 - no idea
M1 0w30 - all Grp IV
M1 0w40 - all Grp IV
M1 EP line - Grp III and IV mix.
M1 HM - Grp III and IV mix.