It's time for a rear tire replacement on my '99 Z3 2.8 and I am thinking about going from a 245/40/17 to a 255/45/17. My reasons are 1) 255 might give me a little better handling, 2) a slightly larger diameter on the tire might help with my Speedo error of +6% MPH.
Before I make this change I thought I would seek guidance from people more experienced with Z3s than I am.