[Alfa02]

This is exactly the reason, there is no "Blue Book" for cars like ours. As others have said, each is basically a one off, even Superformance, BDR, ERA, Kirkham, etc. Factory built cars. Then you have Kits, that could be home made, or authorized Factory Dealers for cars such as "FFR". Then the choice of engine's, transmission's, rear-ends, brakes, suspension, etc. Comes down what your willing to pay, and what the sellers willing to take, if both are reasonably happy then a "good deal". Bring-a-Trailer, is a good source for used Cobra prices, plus lots of comments from people in the know. Hope some of this helps with your price questions, but, trust me there is no correct answer (Price for this car) to your question. Cheers Tom.