Potentially new to X3 - appreciate some pointers please

[GAH]

Hello All - we are new to BMW having spent decades with the other German marques.  Our son went out an bought a ten year old 735i as a first car (OK, he lives overseas so there is distance if something goes wrong..) a super car.  Added to the fact that we have recently hired a couple of X1s and have become a BMW converts. 

We are looking at a 2012 2.0 diesel auto SE X3 in the next few days - mileage is not huge at 78k

I wondered if there are major issues that must be looked into?  The car has history, but it is not all BMW.

We currently have a large 3 litre diesel 4WD estate and simply don't require that sort of volume any more.  We will be doing a fair bit of motorway miles so are looking for something comfortable with some space a touch of grace and ideally enough under the bonnet not to make it labour.  As we are involved in some mountains in winter, the 4x4 element is important for us too.

Anything I should be looking for which we should avoid?