Mario Mini X Series Arm Compatibility Guide

Regarding your question about whether the Mario Mini X Series 2.5-inch and 3-inch arms are the same, please see the explanation below:

The Mario Mini X 2.5-inch and 3-inch models use the same arms. Since these arms support both 9×9 mm and 12×12 mm motor mounting patterns, you only need to replace the motors with the corresponding specifications to switch between the Mario Mini 25 and Mario Mini 3 configurations.

Additionally, the motor mounting pattern on the arms of the Mario Mini 35 and Mario Mini 4 is fixed at 12×12 mm and does not support 9×9 mm motor mounting.

The following image shows all arm variants together for comparison.