Ehh,if you live in America, expect the typical euro tax. Also a little side is that you should never trust the complexity of these newer electrical units on 'luxury' models. I personally have frustrations with how cheaply the  side mirror motors are produced in some of the X5 models. Super fragile the assembly and the thing itself. I've heard that the particular one you are looking at has everything from electric gremlins to completely seized engine for no reason whatsoever. Plenty of stories on limp mode and so on. Seems like these particular ones also took a book outta mini Cooper and have issues with water seals with reports of water damage carpets and frying components because bmw likes to hide electrical components in the carpet and so on as well. But you know, just be a tad hesitant. Lol.

If you must have one lease them only and keep under warranty and return before the warranty expires.  These are all overengineered German machines full of technology and will cost a small fortune every time something breaks or needs repair - and this one is a hybrid (even worse!).  Also, companies like BMW know the vast majority of people lease their vehicles so they cram a lot of technology and features into their vehicles so the lessee will continue staying with them as well as get new lessees.  They are not in the business of making vehicles that will last a long time without breaking (like a Toyota or Lexus).  Also, good luck finding a competent mechanic that can work on those vehicles (especially with all the electronics and being hybrid) - if you find one they will cost more and you pray they are competent in the first place - and if you have to go to the dealer they will definitely charge an arm and a leg.

Yes, it is reliable in breaking. 

The X5 is one of the worst (if not the worst) SUV you can buy in the US. 

First up that X5 is a Plug-In Hybrid, which makes it a bigger money pit than the standard X5 because of all the extra complexity in the powertrain, although probably better than the V8 X5's which are rolling piles of junk. If your wife has to get one, I would tell her to lease a brand new one for 2-3 years and then she doesn't have to worry about the insane repairs.

BMW = Bring Massive Wallet

I drove a 2007 X5 for 4 years between 2016-2020. It was reliable, but cost an arm, leg, and torso to maintain. Heck I spent more money maintaining the X5 in 4 years, than 1999 Honda Accord in 21 years. 

Now with the 2017, assuming it was remotely reliable (which the comments above beg to differ), I wouldn’t even recommend the X5 because it cost too damn much to maintain. 

Unless you have deep pockets, I don’t recommend the X5 nor any BMW for the long term.