Editing rage cost

I'd like to change the rage cost of bear form's Lacerate spellid: 33745

I assume I have to dig through the DBC files and I have been, but I still haven't figured out how to change it all that much outside of reducing the AP bonnus and increasing cooldown.

How would I go about editing the rage cost of Lacerate from 15 to a higher value? (4.3.4 cata)