FB20 Engine Compatibility

[Pitteach]

I have a 2012 Impreza Sport Premium 2.0 non-turbo with 187k.
I have an opportunity to get a low mileage used LKQ engine at a very reasonable price.
The donor engine matches the one in my ‘12 but it came from a 2015 model.
I called LKQ to see if it would work and they said it is not recommended but couldn’t say why.
I am hearing that the reason might possibly be due to the ECU and/or the wiring harness not being compatible.
Looking to see if I its possible and sensible to try this. Could I use the intake from my 2012 on the ‘15 engine?
Thanks

 

[bmart]

Look up the part numbers for the engine, ECU, etc. and see if they're the same or in the same line of succession part numbers. Easy peasy. Impreza/WRX forums can likely help the most.