In case anyone likes to cross-reference part numbers just for fun; here is the p/n for the stock aluminum intake tube. There is a similar version of the tube that is made from plastic. This is shown below. There is even supposed to be an intake tube which curves over to the right instead of to the left. I would really like more info on that style tube.

As mentioned above, some E30 M3's came with a plastic 90° intake snorkel, as opposed to aluminum. It is what I consider to be an unusual piece, although it may have been common on later production E30 M3's. This one was on Matt Weimer's car before he converted to the Evo III unit. The p/n for this bent plastic snorkel is shown.

Just for clarification, here is a different shot of the stock air inlet path on an E30 M3. This is for U.S. cars where the air is drawn in through the black plastic grill over the tow hook cover. In this case the 90° intake snorkel is the plastic design as was originally installed on Matt Weimer's car.