=== Difference 9 - Robot Shoulder Mounting Screw
Megatron uses screws to keep the robot mode shoulders connected to the torso sides. Predacon uses pins.
=== Difference 10 - Elbow Joint Screw Size
Here's something related to another difference. The screws for Predacon's elbow joint are significantly smaller than those on Megatron.
The main reason for this is that the forearm hole at the elbow joint is smaller on Predacon.
=== Difference 11 - Paint Apps
Ok, another obvious one. Predacon and Megatron have different paint apps. This will be fixed much later in the process.
=== Difference 12 - Brown Plastic Shade
This one causes a visual difference that will be noticed, but I don't think the lighter shade of brown really causes any problems, providing that you can't see any of the original darker brown anywhere on the figure. If its uniform, it should be fine.
=== Difference 13 - Mini-Con Pegs
Ok, I didn't bother taking any pictures of this simply because its a no-brainer. Predacon's got them, but Megatron doesn't.