Frank Van Alstine ( of Van Alstine Audio) apparently found a problem with the crossover in the S2 801's yrs. ago; engineered a fix, and B&W upgraded the crossover in the S3. He is usually very open to discuss this with 'Goner's. His number is on his AVA Hifi website and he usually answers himself.
I have read the S3 crossover is a significant improvement; I have an earlier model (the 801 Series 80), more primitive but still very enjoyable and there is no listener fatigue at all. The bass is full but somewhat 'loose'; these speakers eat up the power amps so make sure there is plenty of juice to these babies. They sound better at mid or higher volumes. Good luck.
I have read the S3 crossover is a significant improvement; I have an earlier model (the 801 Series 80), more primitive but still very enjoyable and there is no listener fatigue at all. The bass is full but somewhat 'loose'; these speakers eat up the power amps so make sure there is plenty of juice to these babies. They sound better at mid or higher volumes. Good luck.