Are you really sure you'll get good bang for the buck on the 1.3gHz upgrade? I'm not arguing with you (believe it or not), but I don't think that I'd ever notice the difference in my own uses for this machine.
I'm not really sure. I'm just going to do it because I'm already going for the 512GB SSD, and the processor upgrade should only be $100 or so. And it'll be my only Mac, so I just might as well do it.