When you were installing the temp/voltage sensor did you happen to possibly remove the ESC or steering servo wires from the reciever? Sounds like you might have them switched around. I don't think you could've done that in the Link app.
Before swapping fluids, I'd get stiffer springs.
Are you still running the springs that came with the shocks? If you are, those being softer springs might be doing more absorbing of the torque. That's actually an improvement for handling, but obviously for stunts it's a negative. If you're not looking to swap springs for stiffer, I'd go with a...