difference between 2014 and 2017
 

Hi All, New to the forum with minimal knowledge with Porsche. Owned a 2001 C2 back in the day but have mostly been an AMG guy. Recently sold my tuned E63 which was loads of fun but am now in the market for a Turbo or Turbo S. Curious to know what the difference is between a 2014 and a 2017(both S and non S).
Also, what should I look for when viewing cars and what to expect while owning one?
Known issues?
Maintenance?