I bought cheap-o batteries with only 35C, and I have issues with them. Running a castle monster x esc, but I have to leave the punch setting on low because it hesitates so bad above that. I personally would go with at least a 50C battery. My next ones are going to be 100C tho.
These be the ones incase anyone is interested. Should provide tons of runtime! http://www.rcjuice.com/lipo-batteries