Valuation depends on the reason....if your going thru a divorce and you want the 911 on your side property settlement ledger, I'd say $6,500 tops
Seriously....beautiful car.
As to the G50 Carrera's, I found an 87 3 years ago with 100K miles, that has made a wonderful daily driver (i.e., wear on the driver's bolster, minor paint fading on top that waxed out nicely, etc) for $15K. So they are out there, just have to hunt for them as I found this one in N. Ga.