M100 IIRC is supposed to be the same as a TM spring. M90 90%, M120 120% etc.
Although there are companies who have their own system. Best bet is to check out the spring chart somewhere on this forum (it's also been posted around on redwolf and Arnies IIRC).
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE