I would consider this as one of the essential upgrade parts for the E10. The stock plastic one doesn't hold the motor in the optimum position for long. Before I had this installed, I was practically tightening the stock one every other ride or after a big bang. With the Yeah Racing mount, it is very very secure now and I have yet to tighten it.
The bad part about this is lack of instructions and difficulty of installation. There are 4 screws of different lengths, figure it out first before screwing in. I thought I got it right the first time but motor couldn't move cos one of the screw was too long and it was blocking the motor movement.
Anyways, here's how it should work:-
1) The shortest countersunk screw is to be used at the chassis bottom to hold the "bridge".
2) You have the remaining 3 screws where the longest and shortest is used to hold the braket to the motor.
3) The middle length one will be used to adjust the angle of the motor (gear contact) and secure to "bridge".
The last part might be tricky as you have to dismantle the front bulkhead in order to have a clear space to adjust and tighten the screw. Once done, step back and check out how strong the motor is secured to the chassis now! :)