I'm no expert but the last time I saw a four speed in a BMW they were in the 70's 2002 model. I have never seen an E30 or newer with a 4spd. I think even the E21 have 5spd, but I have never taken a good look so I am not positive. As for the engine, all 318 motors from 1990 to 1995 are the same regardless of 318i or iS. They changed to 1.9L in 1996.
Anyhow, I am confused by what you are asking so hopefully my info is relevant in some way.