I know a couple of racers that have switched from c-12 to 113 and swear by it.I used c-12 for quite a while,and bought some 113 to test with,but did not get to do back to back testing yet.
I can tell you it is the best smelling race fuel I have ever witnessed.
The racers I know swear it is more consistent and picked them up a solid tenth,and they also jetted up 4 sizes.