They made almost 200k 986's, but due to the cost of maintaining them properly, I agree with everyone else, well maintained 986's will do very well longterm. It also doesn't hurt that they are fantastic handling convertible sports cars.
I also think the design of the 986 is superior to later models, which will make the 986 more attractive to collectors over time. The 986 is the model most in keeping with the original 550 Spyder design inspiration.