Provenance and originality
Start with identity, paperwork and originality. For the Mazda RX-7 (FD), the strongest cars have a continuous ownership file, matching chassis and engine details where applicable, original manuals, invoices and evidence that major service work has been carried out by recognised specialists. Original paint, factory interior, uncut wiring, original sequential turbo hardware and documented rebuild history determine whether a car is collectible or merely usable.
