what do you want to do?
The best stereo is from 2 projectors with polarising glasses, which you can do off a dual head card if either its your own application and you set the two heads to render with an offset, or you can get the application to do that. havent done it for a while, but it is very convincing.
The quadro support will do this for any application, or will do some of the shutterglass stereo modes (that are by comparison not very good). They also support 4 buffer GL, which many old SGI programs use but the program still has to support stereo.