Surefire L2 MC-E Mod

[Bogie]

I have a old L2 sitting around that could use a upgrade, now I know the MC-E makes a good choice (unless there is something better, I am not up on the newest emitters). But I don't want to hack up my stock head so short of getting another L1 head, is there one you guys recommend as a base ? I have a E2D head that I could use as well.