2 years ago (Jan 2015) I put my 1973 1/2 911T on Bring a Trailer's auction. Everyone said I'd get around 40 to 45k When the bidding ended I got $60,000 I bought the car in 2008 for $25,000 and put $4,500 into the car namely a 3.2 Carrera engine. Not a bad return for 7 years of ownership.
http://bringatrailer.com/listing/1973-porsche-911t-coupe/