I've got the Michelin PP on my Z, next set I'm getting is the dunlop TT. The michelins have a lot more grip than the stock tires. Different profile too, not at steep in the front, more of a flatter tire. This will make the bike less twitchy on tip in. On the z, tire size makes a big difference. I'm running the 120/70 front, and 140/70 rear. With the dunlops, because of their small profile, they will be quicker to turn in. Plus less rotating mass = less stress on the engine and "quicker acceleration".