For RM setups the type B chassis braces in #TD320269 and #TD320270 have been redesigned to allow for removal of the top brace independant to the lower brace and also allows for easier transmission case removal. The lower brace doesn't hold down the transmission case and the screw joining the upper and lower braces mounts from the top.
The type B MM bumper is also included in #TD320269, pic below.
