I agree w/ the comments that whether we move cars down or add a new class, it is basically the same. And, YES, Andy, the moving down approach does mean obsoleting *cars* in C, but Greg's point is that it doesn't obsolete the *class*.

I disagree Greg. I think the better approach is to add the class at the top. By doing so, you have more stability. Instead of *every* class having change all the time, you simply have the change in the *new* class (and eventually in the low class when it dies). The classes i the middle stay constant. More stability is likely to keep the competition tighter. My $.02.