The cockpit seems a touch larger, and there is some extra (support) plastic attaching the SRM and shoulder paldrons that sticks out slightly, but overall, it's not bad.
Comes with 4 sets of arms, mirrored, meaning you get 2 MG right arms, good for modders to make the Stiener missile versions or even the 6C.
Also has 2 sets of legs, one for a standard walk and one for a running pose.
Kinda torn if I want to keep it as a standard Battlemaster or use it for a 6C. Only downside is there is no center mounted laser port, so the Red Corsair/Royal is not an option out of the package.
Last note, the premium ball sockets are not compatible with the metal release, unless you want to lose detailing on your metal body, or get creative shrinking the arm ball joint in some way.