Product review (4 stars): Good Kit -- Not perfect -- But Huge Improvement
This seems to be a good kit that replaces many, though not all, of the original plastic parts with metal.  Unfortunately, the axles of the wheels, one of the weakest links of the original system, are still plastic, though they are now held on with metallic screws.  As one previous reviewer mentioned, maybe Kitchenaid (or someone) will make a replacement available for just the wheels and axles, as I suspect these will eventually wear out.  But this is a far more robust system than the original, no question.  I also agree with other previous reviewers that the original design was defective and that Kitchenaid should have made these parts available to owners of their products for free (or at no more than cost).  Too bad that nowadays about the only thing that prompts companies to do the right thing is the threat of lawsuits.  Only the smartest of companies have the foresight to create customers for life.  Kitchenaid's approach works to quite the opposite.