I replaced my second set during a riding trip just last week. They were Pirelli Rossos. The rear was worn down to the cords, and the sides were scuffed up completely to the edge. (No chicken strips.) The bike felt a bit mushy on the second to last ride, but I realized later that the inflation was WAY low. Once I filled it up, it seemed to handle fine for the rest of that day, and the following day on the ride up to the dealer. A bit rough, but that might have been the road surface on those particular rides. However...
I simply cannot believe how much better the bike feels with new tires. I went with a set of Shinkos, since that's basically all the dealer had in stock that didn't cost a fortune. The second I started riding it out of the parking lot, the difference in feel was simply incredible. The Pirellis wanted to turn easier, but the Shinkos are smoother and seem to offer a better feel when cornering hard.
I say replace the darned tires. You'll be glad you did. And yes, do a burnout with the old one, first. (Duh.)
-Matt