I had to file the housing a little for the small L bracket to fit perfectly flat as the axle had a small slope starting right there:

You see better what I had to remove here, see the top compared to the bottom of the axle:

And mocking this up again with the watts linkage in position:

And a couple more shots of the axle with almost all its brackets (will need something more to mount the shocks, it's already designed in cardboard but needs to make in in metal)

The tamiya sport tuned motor I just received, and the traxxas turnbuckles so I can have 4 links (I got two off of my traxxas nitro stampede)