The fuse holder underneath the glovebox that your referring to is the
bcm.
If your going to buy and fit the cosworth inlet I advise you to also fit the cosworth camshafts and then have your remap to suit as this will give you the best gains.
Why is it that you trying to find where your
PCM is located?
If considering doing an engine swap it is far easier and cheaper to run a standalone
ecu and to have that fitted. Run your existing one in parallel to provide signals to your instrument cluster and the rest of the cars modules.
If you run the OEM module you will need to have it all configured using ids which very few non dealership garages have and I'd be surprised if a dealership would want to get involved with a conversion.