You should find out more about the Carrera. Need to know WHY it is being offered at $25k.
Engine and tranny professionally rebuilt? Euro model? Track car mods (brakes,suspension, etc)? If it has these, it may certainly be worth that much. If not and it is completely original it would be priced in the teens given the mileage.
The headlights alone are enough to make the 996 19K
(joke).