Most iS's came with 3.73LDS's but it was still an option (pretty rare) on non iS car's. You can tell by checking the metal tag on the bottom of the diff, it will say 3.73S instead of just 3.73.
325es's came with a 2.93LSD
91 318is - M50NV (gone)
02 WRB Subaru WRX EJ207 forged, 320 AWHP stock turbo.
85 - 325