Can I swap my 2005 impreza outback sport 5 spd manual (not turbo) engine or is it even worth it? Need advice!

[myllwood]

Hey team, I need your advice. I have a 2005 Impreza Outback Sport 5 spd manual. 138k miles. Shop just informed me that the head gaskets are going to go soon (which I know is a common problem for these engines). The repair will be about 3250$. The car is otherwise mechanically sound, no exterior damage, a small spot of rust on the rear wheel well that can be repaired (it's less than an inch). 

My question is, would it be possible or even worth it to swap it with a new gen motor that has this issue fixed? If that is possible, what motors should I look into swapping? 

I'm not very experienced with this process, so a shop would be doing the work. 

Any suggestions and advice is appreciated!