I'm pretty certain all S3's will be OBD2, and that the only OBD1 8L is a pre-facelift A3 with an AGU engine.
The information is right for A3's, but I couldn't give a flying squirrel about S3's.
Regardless, any powered OBD2 scanner will be able to read the codes and give full access to an OBD1 system. It's only the bluetooth sender units which won't work with OBD1.