I have a fair amount of experience with Pirelli tires. I run Dragon and Diablo Supercorsas on the track and have run Diablo Corsas and standard Diablos on the street. I've gone through many pairs. MANY.
It seems to me that the Rosso may just be a rebadged Diablo or a replacement. "On the street" I absolutely loved the regular Diablos, i.e. Rossos. They have a sound 3000+ mile service life and provide great grip.
I don't know how close the OEM tires are to the Dragon Supercorsas (how different can they be?) but you may feel a difference in the bike by switching away. The Supercorsas have a much more flexible side wall and IMHO provide better feedback than say, the Corsa III's, because of it. But then, I feel that when I'm knee down taking corners. On the street you may notice nothing. Or you may notice just a tad more "harshness" or "bumpiness" from the tire. Not a big deal at all.
These bikes come from the factory with DOT Race tires. Expensive and certainly not the best thing for riding on the street. I doubt they ever get up to proper temperature and their service live is dramatically shorter.
I like the Metzler suggestion. If you really want a comparable tire to the Supercorsa that has a longer life I suggest the Metzler Racetech K2. Made by Pirelli. I believe it basically has the carcase of a Diablo Corsa with the rubber compound of a Supercorsa. On the track they don't provide as much feel as the Supercorsa, but they provide the same grip and last a helluva lot longer.
But again, if you're just doing street riding, the Diablo Rossos should work amazingly well. My personal preference for the street are the DCIII's but that's just semantics.