Well, I've put a little over 100 miles on the new Dunlop GPR300s and so far, so good. It's hard to do a comparison to the Diablo Rossos because they were so badly worn that my last impression of them isn't a valid comparison against a brand new set of tires. Still, now that I've gotten over the "new tire feeling," they no longer feel "twitchy" to me. In fact, the handling is just flat out wonderful. I haven't had a chance to take a run on my favorite twisty roads, but impressions from highway on/off ramps is very favorable. It also feels a whole lot better going through water, but considering the front tires I removed were damned near bald that shouldn't be too much of a surprise.
Anyway, these tires were mounted at a little under 9,000 miles on the bike, so it'll be interesting to see how long they last compared to the Diablo Rossos I replaced. Also, please note that these are RADIAL tires like the Diablo Rosso IIs they replace. The Sport Demons (which were on my 2016 S) were bias ply. This seems to support my observation that motorcycle tires act the OPPOSITE of automobile tires in that in automotive cases, radial tires far outlast bias ply. In my observations, in motorcycles bias-ply tires outlast radials. Stay tuned for how long the GPR300s last.