I've got a 2017 S60 T6 R-Design w/Polestar Tune, and I absolutely love it. I bought mine with 13 miles on it last November (and still got the CPO warranty) and have put almost 10k on it so far. Like rallyr32 said, not much in the aftermarket department yet but I always keep my eye out just in case something neat pops up.
Once you get out on the road and have a chance to open it up, it's a hell of a fun car to drive. My only complaint is the premium stereo system could be a little better (I've heard the new generation premium audio blows this out of the water), so I've started to look around for aftermarket solutions.
Good luck! Give us an update after the test drive