I've seen some nice 915/3.2's list for very low 20s lately.
I saw a nice under 100k miles 1986 Targa go for $19k
I've seen an '88 G50 list for $23k. 125k miles.
80k miles for $21k
http://forums.pelicanparts.com/porsche-cars-sale/779851-1986-911-targa.html
116k miles for $21k
http://www.excellence-mag.com/classifieds/15930#.UnhIv_m-1Bk
After summer peaks, do prices dip like this each year?