OEM FRS/BRZ Radios
 

Looked around with the search function and didn't find anything or that I'm just blind before coffee.

I was wondering if the oem base radio can be swapped with the oem '14/'15 unit whether it's a BRZ/FRS (plug and play)

The short answer is Yes. You will have the connectors that you need for all the basic stuff but if you don't have satellite radio/GPS in your car, then you gotta get the antenna to add those features. I don't remember if the radio antenna is the same, but I suspect it is. The basic connectors for Speakers/Power/Aux inputs/Phone Mic should all be there.