It'll bolt in easily enough, but as AJP says, the biggest headache is the wiring and ECU(s) comms. There will be many fault codes to deal with, not to mention immobiliser issues. If you can get the complete harness, clocks, ECU(s), CAN gateway and key etc from the donor car, your life will be a lot easier.
It's definitely worth doing if you're thinking of big power.
I went through all that when fitting an R32 engine into a Corrado. The mechanical stuff was p1ss easy. Getting the ECU to play ball was a complete nightmare, although on the older ECUs the immobiliser can be deleted, which was useful. Not sure that can be done on the MK7 stuff.