newbie in desperate need of help

I'm in need of some help/information.

I have a 98 rs coupe automatic that was overheating. Turns out it was a head gasket leak and possible crack somewhere in the head and/or block. So to avoid any more issues with that motor I'm looking to swap to another one. I'm also looking to swap to a manual transmission. The part I need info on is compatibility. I found a 2001 impreza L coupe manual with a rebuilt 2.5rs motor in it as a possible donor car. This is my first car and my own mechanical experience is mostly with motorcycles and I have very little knowledge on exactly whether or not I can just swap the motor and all the manual trans parts with what's in my car. I'm not sure if the donor motor is sohc or dohc yet but would that effect the compatibility with my own car either mechanically or electrically if it works in the donor and if I'm gonna be doing a total swap? Also would a total swap be possible and what kind of labor time would I be looking at if I had the work done at a garage? I'm not planning on putting my current parts back in the donor.

Any information would be very helpful to me