As for warranty there are no questions asked. The 225/255 setup is probably your best bet especially if you end up going with the PSS. I have no problems whatsoever with the speedo, ABS, rubbing and etc. and im running everything stock. Just get a alignment and a balance and you are good to go.
Based on my understanding is that the PSS will also outlast the run-flats, but im sure someone can chime in on that...