This has been answered a number of times. I haven't done it myself, but this is what others have said.

Converting m05 to m05 pro ver2:
- A parts are a direct changeover
- motor mount should also be changed to m05 ver 2 type. (Although some don't bother)
- arms can also be changed to take advantage of the droop adjustments.
- if you want to run a standard square pack but don't want to use tape, m03 C parts can be used to hold the battery. Some small modification is required.
- use a small amount of foam inside the A part of the chassis to help stop the battery moving around.

Hope this helps.