I had the original Conti SCs on my e46 M3. They were excellent. Good ride, quiet, stayed balanced and wore well. I can only imagine that the SC3s are even better. I replaced the Contis with PS2s and noticed very little difference other than the PS2 could take two days of RoadAmerica abuse and show little wear. Contis and Michelins are the only tires I would put on a BMW.
I would definitely consider the SC3s.