For an example, I saw my old 914 just sold for about twice what I sold it for last spring. I sold it to a guy in the bay area, he had it for about 1 year and put a little money into it, sold it for $1000 more than he bought it for, and the dealership he sold it to recently sold it for $16900.
Here is the back story if you're interested:
http://www.914world.com/bbs2/index.php?showtopic=251568&hl=
I think $12-13k is low if you're patient, more like $15k+.