Fabulous stuff MLCMM, keep it up. The 200km barrier looks set to be smashed.
Re the shoes - isn't it the case, though, that the tread and uppers are not so important? What counts, I think, is what you can't see - the cushioning. When that starts to break down, impact increases, as does the chance of injury. Although if most of your running is on the tready, that probably doesn't apply.