I hear this kind of thing often -- this brand of body (or moreso seat) will bind up the kart.
I don't think your kart knows what "brand" is being bolted to it.
Now, I think there's something to be said about following the recommendations of the manufacturer (ie seat design, placement, etc,) but I have yet to see how a body or seat "brand" can "bind" a kart if it is mounted properly. I could see if the body were something extreme (like 1/4" thick fiberglass or plastic), but most bodies are built very similarly.
Mount it correctly and it will serve you well (with no bind.)