I checked the FastLane link in the header of this message. There is no 1992 320 in the US so I referenced a 1992 318 (E36/M42). A Bosch idle control valve is discounted to US$117. For a 1992 325i (E36/M50) the equivalent part is discounted to US$92.
I don't know much about BMWs. I'm just telling you what's obvious to an average enthusiast based on your descriptions.