I had this custom waiting for at least 2 years. This is one of my favorite figures of all times. Together with WFC Optimus Prime are one of my favorite iterations of this guys, and were of my motivations to learn customizing. However I didn't feel ready to engage into them since I didn't want to blew it. Now, almost 3 years of experience later I decided to engage on Megatron since I think it was due time.
The changes to this figure are as following:
+ Custom hands and forearms. They were 3D printed
+ Custom Megamace also 3D printed
+ Custom arm Cannon as well 3D printed. One purple led was added to the Cannon with a button switch accommodating the design.
+ Full repaint of the figure to go with the War for Cybertron schema full of battle damage and purple lights on decepticons.
You can see a comparative of the original design and color schema vs this change.
I don't want to take credit for the 3D designs. The designer of all of those is Fakebuster, I just printed them at shapeways accommodated and painted them.