I've got somewhat of a build thread in my signature. The last couple of pages are where the meat of the CUA discussion is. For putting the motor into MK7 vehicle, it's really not much different than the CRUA as long as you swap the fuel system over. The CRUA ECU is for solenoid injectors, vs CUAA being piezo and CP4.2. A LOT of shared parts/sensors between the two motors being they're both EA288.
Any swap into a wagon would need the ECU and appropriate wiring harness, but outside of that could be relatively straight forward. The CUA uses a massive DMF that requires an 11mm spacer between the motor and the DQ500, I didn't need that since I kept my 02Q gearbox.
An AWD version would be pretty sweet. Shoot me a PM if you have any other questions.