I am thinking of committing a large amount of cash (for me) on a special car to enjoy in my retirement. Which of the following three cars which I am considering is likely to retain the most value over a period of ownership of probably at least five years, with fairly light use?

I am trying to choose between a 2015 Cayman 2.7, a 2013 Boxster S and a 2010 997 Gen 2 911 Carrera. Each one is priced similarly. All have less than 5000 miles on the clock and are literally "as new"; all have the PDK gearbox. I think the 911 is probably the safest investment, though it's only a fairly basic specification, unlike the others. Which would you recommend?