Do you have any suggestions for installing the MN MODEL MN168 brushless rotor?

MN MODEL MN168 outer rotor brushless set low-speed torque compensation ESC

The outer rotor torque is really good. It is easy to modify the car but difficult to install it. It is a bit difficult to install the car shell. You can refer to my plan. It requires a little cutting before it can be installed. It will be easier to install it by removing the seats.