Having checked the EA21R Parts Catalog (see Manuals), there are two crown wheels for the "without LSD" case (Fig 45). Not being able to read Japanese, I can't tell what they are in terms of ratios, but the first is the same as the EA11R, and is for the manual transmission, and the second is for the auto transmission.
For LSDs, see
https://www.race.fi/en/product/44791a/cusco-lsd/151-22142/suzuki/152-7157/cappuccinoThis link
https://www.suzukisport-racing.com/english/sales/cappuccino/list/index.html shows that Suzuki Sport did not offer alternative differential ratios.
EDIT: Thinking about it, the auto box has only four speeds, so the chances are that it has a higher (less reduction) diff ratio.