Originally Posted by 0010

Hi Riko,
Shock oil won't do anything for the ride height of the car. If I understand what you are calling sag in the rear, you are saying that the rear of the car is sitting to low. If that is the case, use the spring collars to adjust the ride height. There are red collars with a machine screw in them at the top of the spring. Loosen the screw and slide that collar down until the rear sits at the height that you would like. Set both side to the same setting.

You also mentioned something about building your ball diff and tightening it as much as you could. That is probably not the best way to do it. Typically, you want the ball diff to be as loose as possible without slipping under acceleration. This will give you the smoothest differential action. As far as break-in, you can hold one wheel while you run the motor slowly (not full speed!!!). Often you can just advance your throttle trim so that it is actually moving the car at neutral trigger, then hold the wheel for a bit. I don't know if I would do all 8 minutes at once as you could build up some serious heat, but a few minutes at a time until the diff feels really smooth when you spin the wheels by hand.

Hope that helps and good lcuck!