I recently acquired a 2013 Mini Cooper S Countryman with a bad engine (92K miles). I found a used working engine from a wrecked Mini with 62K miles. I currently have the old engine out and the used engine ready to go back in. It does not appear to have any oil or coolant leaks.
I'm looking for recommendations on what to replace and or look for before I install the engine eg. water pump, t-stat, hoses?

 

It would also be a good time to pull the intake and have a look at the valves.

 

I would probably do the timing chain guides & water pump while the engine is out of the car.

 

+1 timing, valve cover, water pump, thermostat housing, water pipe.

 

The day I posted this, I had already placed an order for spark plugs a broken coolant pipe, filters, and spark plugs. The water pump and thermostat housing make sense as well, but did the newer N18 engines have issues with the timing chain and guides? I have a later 2013 build date.
The intake valves seem fine. I didn't see a lot of carbon build-up, but it would be nice to clean them up with something while it's still accessible.

 

take a look at the oil filter housing and turbo oil feed line. Although they may not be leaking, it might be a good preventative measure to replace them. Also, while the engine is out, if the car is Automatic, consider loosening the transmission fill plug for later service. with engine installed, it is harder to break that bolt loose.