I did 85,000km in mine, and it was rock solid.
Check the tyres very carefully - uneven wear could mean that even though the outside edge of the tyre looks good, the inside could be stuffed. Replacement tyres can be $400+ each, so you don't want to be replacing any if you can help it. I was regularly getting the alignment done, and even then didn't get full use out of my sets of tyres before they had to be replaced.
If buying from a dealer, ask them to apply the latest SYNC3 software update, and also ask for a map update too. Don't let them fob you off that the SYCN3 updates are done over wifi, they have a USB they insert which works and is quick too.
You would want to check the aircon is working and cold across all vents - if some vents are not cold, then there is a leak. I had no issues with mine.
Find out when the battery was last replaced - you will most likely need to replace it again at the 3yr mark.
Check that glass roof for any cracks or damage - I was told that the replacement is hideously expensive. I always worried what would happen on an unsealed road or hitting a pothole accidentally, but never had an issue.
The only other item I can think of is to suggest you start thinking about what you will plug into the 240v mains outlet you are going to get in the back! Very cool, but I don't think I ever got to use it!
Rock solid car, great balance of performance and all the latest features - but you are also (hopefully) getting very cheap running costs too.
Enjoy!