Most servos arn't rated for 7.2v alot of guy's are running without voltage regulators though and say they're holding up fine .It's not the 7.2 that will kill em as much as the 8v it can be at after charging. Hitec's TG series have been tested to run on 7.2 a rep said they won't die any sooner. There are JR high voltage servos they cost. If you had to take out end point on steering or brake you might get away with moving one hole closer in the horn= more speed and power. With the right lipo and 6v regulator you will see more consistant longer lasting power.