If the RX and servos are capable of 7.4V I wouldnt change it. The RX says its good up to 8.4V so np there.
Punch could help, Id try adjusting that. Motor timing isnt something I've ever played with a whole lot so I'm not sure about that one. One of the race guys could better address that setting.
Like TNT said, try recalibrating. It could just be a sensorless set up issue. They are a bit jerky on start up compared to a sensored set up but whether or not you're experiencing more than typical jerkiness is hard to say without a short video clip or something so we can see what its doing