Thanks again for the comments guys The C55 I ran is completely stock. I can not stress enough how much of a difference a healthy (well cared for) and maintained car runs compared to some that aren't.
Not taking anything away from the silver one I ran, it is an immaculate car and exceptionally maintained. It shows the differences between the 02 and 05 M3's and why the Face lift M3's fetch so much more value.