Thats the beauty of Lipo, there is not that much difference from a 40 dollar pack to to a 150 dollar pack. I care nothing for C ratings, I have 40C and 60C and the speed difference is identical, remember the thread where the guy pulled his 50C pack apart and found 40C cells inside.
C ratings are marketing hype, one company brings out a C rating and the others change their stickers... I would love to see these batteries tested from an independent source to see the true ratings.
I am not seeing it at the track, not like the days of NiMH where .01v made a difference. Buy a pack and race, my associated 40C is as good as my associated 60C and my IP packs are as good as both of them.