Cool game this new vs. old thing
IMO, everything other than what I am gonna write down below looks better in the new one and overall it gives an impression the old was never able to. Just the coupe I am taking into account but basically the same goes for the convertibles:
Exterior: The side sills, the exterior rear mirrors, the bottom half of the rear bumper.
Interior: The steering wheel, the sat nav screen area with the cap,
are better executed in the old M6. And they practically have the same wheel design.
It is quite impressive that despite being so different in details how they share the same silhoutte in the profile pictures.