I don't think they'll skyrocket any time soon, but I am somewhat pleased that '99 986's with similar or even higher mileage than mine are now selling for about the same or more than I paid for mine 4.5 years ago.
I paid $10k in 2011. A '99 now can go for as much as $9-$11k in my area after hitting a low of $6-$7k a year or two ago.
Definitely not an investment in $, but a great investment in fun!
