What Are These?

[Eddie.]

Engine is an M20B25 from an early E30 325i.

This plug:



And these two:



Would be much appreciated.

[polov8]

given the pipe stub/hole combo are before and after the throttle valve, my guess is there's an idle stablisation valve (ISV) missing, and that 3 pin plug would be right for a typical bosch ISV.

Edit, yup, here ya go:



That bracket in your pic with the rectangular hole is what supports it.

[Jeroen]

The plug is for a sensor for barometric pressure, afaik you can do without it. Small black box that is normally mounted on the bracket for the air filter housing as you can see below



The intake openings are for the idle control valve indeed, also see here: