I replaced my OEM Pirelli P-Zero Rosso's at 12K miles (worn out) with P-Zero Nero M+S. Now, 20K later they are about half worn. These are not on my Z but on a high performance Vovlo AWD wagon (don't laugh, there is such a thing - the V70R). My experience is that the grip is good in all weather but as they wear, they get quite noisy - especially in the heat. I have not noticed any difference in the handling between the summer tire (Rosso's) and the M+S (Nero's) but would not buy the Nero's again due to the noisy tread development. Have you researched Michelins?