I went from Conti3's to the PSS's on my last M3 w/220m's. I first tried the popular 255/275 and surprisingly didn't like the feel/loss of torque. Don't know what it was, increased OD or weight or a combo of both? Anyway, it bugged me enough to lose them and try the PSS's in 245/265 and life was good again.
Whatever size you go with, I'd pick the PSS. You'll get noticeably more grip, wet and dry compared to the Conti's. The PSS's also look wider than the Conti's, they're sporting some very broad shoulders. Luv the PSS!