Nothing EVER changes CMC. CMC is always derived from the values printed in the upper right corner of the card.
Effects that change the amount of mana required to cast a spell never change the mana cost of that spell, nor do they affect CMC. What they do affect is the casting cost of the spell, which is typically the mana cost plus any additional or increased costs and minus any cost reductions.
July 14, 2014 9:42 p.m.
Please remember to select an answer to remove this from the active queue.
July 14, 2014 11:16 p.m.
The last step is more of a courtesy thing. I go through and clear out answered-but-active questions a few times a day. Doing it on your own just saves me an extra step if you remember.