ABC was an option on the R231; the standard car uses Adaptive Damping (code 485) with selectable comfort and sport modes. The overwhelming community advice is that buyers of high-mileage cars should prefer the non-ABC/standard suspension because ABC becomes very expensive when it fails, while the standard setup still rides and handles well.
Active Body Control (ABC) suspension: avoid on older cars
Mercedes-Benz SL (R231) · buying