I know I have the P Zero's, but Tirerack have 3 versions of this tire. So which one is best.

Pirelli
PZero Rosso
Asimmetrico

Pirelli
PZero Rosso
Asimmetrico (Mercedes)

Pirelli
PZero System
Asimmetrico

Also, how long have people keep their original tires on? What is usually the wear mileage that these guys do? I am on 20K miles. My tires look like they might need to be replaced.

I have 5000 miles on and a bubble on each of my two driver side tires. $950 is the cost of replacing both.

I had some tread left, too (4mm). I rotated my tires every 5K miles.

Unfortunately had to change all four tires after a puncture so the Quattro wouldn't go ballistic.