Depends, what do you need to use it for?
sorry I don't have an olight M30 for picks for you.
I definately agree the L2 can be very impressive.
re: do you need an M30 now? Well, did you really need the L2? The standard CPF answer is 'both' when someone asks about two different lights.
What drop-in do you have for the L2? I feel that a solid 18650 or 2x(r)cr123 light can provide sufficient output across many situations. Do you have a pressing need for long throw, big run times, direct access to tactical strobe (M30 feature).
I favour using single cells to eliminate any concern over differential charges across multiple cells (and subsequent venting with flames). I carry additional cells when I plan on using my lights for a while. Unless I'm diving it's simple to replace the cells (and like any good cpf'er I have back-up's for the replacements, all of them tested before hand with my dmm)
Best,
L