Re the mention of Goodyears - I have to add (in my own personal opinion) that I'll never fit another set of Goodyear tyres to any car of mine.
The last 2 sets I had on my Audi S3 suddenly and mysteriously deteriorated to the point where I had several near crashes in the space of a few short days. And that was on an inherantly stable / uncrashable car - I'd hate to think what that would be like in a car like the M3....
Its discussed at length
Here - apologies for the cross-post but it saves me typing it out again.