Engine, wiring loom (im fairly certain), ECU, engine mounts, engine cross member............. To be honest your better of buying a 318 with shoddy bodywork for cheap and taking the body panels off your 316 and putting them on the 318. Or else just sell your 316 and buy a good nick 318.
Its all gonna be fairly expensive unless you do all the work yourself, which would be out of the question if you didnt have the lifts, tools and experience. To pay someone to do it would be 500-900euro in labor alone, not including parts and all for what, an increase of about 10-40bhp. Doesn't make to much sense to be honest.
Iv been down this road in the past with a 1987 celica and a supra T.T. engine (a bit different i know) but it was the biggest financial mistake i ever made.
The ONLY Hellrot Red 323 in the world, emmm except for the other few thousand dotted around the world.
I looked at my engine of 1997 M44 and the ICV doesn't even look like the one at Real OEM. you are not alone in this BMW what kind of part I got confusion. I have an electrical fan and even BMW tells me that I have a fan clutch.