Originally Posted by calvs79
i think i have a m40 lump???
Yup either a m40 or a m43 is what you have.
Both the m42 and m44 are 16 valve motors (basically the 'is motors you are looking at swapping).
Out of those two, I would probably take the m44 if I had the choice (a bit more displacement and a bit more torque and it has a MAF instead of AFM).
As for the swap: I am not really sure if the 16v engines will bolt up to the transmission you have now (definitely something to look at), but aside from that since the e36 came with the motors you are looking at swapping in, you just need the basics: mounts, wiring harness and ecu. I can't imagine it being too difficult