My opinion is that you'd have to be a fairly experienced rider to really notice the differences between an R6S and an R6. It's not really about speed or power but performance and handling. It looks like Yamaha is putting their R&D investment into the R6 while keeping the R6S the same because it was still a great selling bike. So the gap will widen but like I said before I doubt how many people can really tell a difference. And even if you could, I'm not sure how much it really matters in every day riding.