I have the Protek 8500mAh 100c batteries and I can't really notice any additional power from .2VDC on my 4wd SCT. Now, Before I struggle to get 10 minute runs and last time at the track I can easily run 14 minutes with it charged at 8.60. Note that if you charge at 8.4 not just the voltage but the capacity goes down as well. i.e. mines are 8500mAh @ 8.60V but they are 7600mAh @ 8.4V.

P.S. The tracks I run. no one cares about LiHv batteries and even people run 3s on their trucks. I still lap them on 2s tho. 3S SCT is not faster but longer run time which I now can achieve with my LiHv batteries.