Well I don't think the ossie needs changes. Mako as I said could use a med core since its the size of a med bs. That's pretty much all I can think of that wouldn't upset the balance too much. Giving ossies med core would probably make it op.
Personally I want to pursue getting Core a Heavy BS instead, to serve as our solution to bigger problems rather than buffing the Mako to compensate, but I guess that's another matter altogether.