OK, The Parma body posts will fit the outcast body mounts. Maybe 1 wrap of electrical tape around the base of the post would make for a perfect fit. Once I put the Screw through it, I don't see there being an issue with the post to mount connection.
NOW. the actual post is about 30% thinner than the stock Kraton Posts. So if you already have holes for the Stock Kraton Posts, then these might not be great. In my case I am going to try out the Traxxas screw down body clips, so I am not sure how easy it will be to drill into the thinner post.
So yes they fit, but are they perfect? no.