The spider/arm cracking problems were related to a stress raiser created at the junction of the arm and the crank. I don't know what year, but Campagnolo solved the problem by putting a small radius at that junction. I'm pretty sure but not positive all Super Record cranks arms had the radiused junction. The fluted/non-fluted arms are not related to the arm/spider failure, and to the best of my knowledge are an aesthetic change only.