I just put a Metzeler Roadtec Interact Z8 (sport touring) rear tire on yesterday. It should be good for about 6K miles. I'm using a Metzeler Sportec M5 Interact (supersport) front tire. Nice to have the supersticky tire up front, and given it's the front tire, it also looks like it might last about 6K miles - we'll see. If so, this is a NICE combo for the V if you're canyon carving and street riding IMO.
Absolutely. Old rubber isn't as good (grippy and puncture resistant) as fresh rubber. Ive replaced more tires from dry rot than wear and punctures combined. A good tire thats old is not even worth half price IMO. I wouldn't take an old "new" tire for free on anything that gets ridden far or fast.