See the XTS section for more details, but you are in a great position when it comes to "things to watch for". The XTS is about as problem-free as (current) premium cars get. You will have to deal with a dead CUE screen at some point, and likely a strut or two. You might have to replace the air-ride compressor. Other than that it's the standard 4000lb premium luxury car stuff - weird tire wear, wheel damage and balancing, hubs, warped rotors, and the occasional electrical glitch that you fix by letting the car sit overnight.
So drive and enjoy!
Thanks for the reply! Prior to the Volvo I had a 08 Mazda Miata and 01 Honda s2000 so the 4000lb Luxury car thing is new to me. Lol