Like BB says the engine loom should not be too hard to fit, It seperates out from the rest of the loom very easily. I kept my existing loom for oil pressure switches, starter and coolant temp etc, just used the passat loom for all the engine running stuff.
Once it has been seperated out, identify the wires required to be patched into the fuse box and patch them in, then plug all the bits in on the engine side.. Well thats what I did anyways.....

Make sure to grab the wiring for the diagnostic connectors before you bin the passat body also.
It runs from a plug near the fuse box (which plugs into the engine loom) along the drivers side sill to under the gear selector where there are several two pin plug connectors, blue, black and white ones can see them in one of your pics.
Having the diagnostic connectors can be helpfull, you can easily read the fault codes with an LED if you have any problems once it's up and running.