I just bought a set of 205/45/16 for my stock P5 wheels. They throw the speedo off by the same amount as a 205/50/16 (45 series is 1.7% too fast and the 50 series is 1.7% too slow). Both sizes are easy to find and lots of choices for brands and performance ratings. I personally went with the Falken Ziex ZE512 because I have had them in the past with no problems and I got one hell of a deal on this set.
id get 205/50/16 just for the wider contact patch...i like to take corners fast so id prefer a lil more rubber on the road...and isnt it possible to have the speedo calibrated?
I put 205/50-16's on mine before I put the new 17" wheel/tire combo that I'm running, and will put those back on for the winter season. Happy with that choice... a wee bit taller, but a less harsh ride. Definately my recommendation on the route to go.
