Do i need to run a alum. servo saver? I have a JR Z9100T servo. Which one works the best.

the truck already has a servo saver built in the steering bellcranks. I've had the plastic servo strip on me once so I put on an alum servo arm and have not had any problems since. I also use that same servo as well.

just make sure there is some give in the servo saver if you are going to put an alum arm on.

I spaced that one lol, what you you mean by give?

Well with some effort you should be able to make the servo saver unit flex and see the spring compress. If the servo saver is locked up all that force will go right into the servo and can break the little plastic gear in there or worse cause the motor to burn out which is expensive to have fixed.