Ford Sierra Cosworth Buyer's Guide
Five tracked Sierra Cosworth sales, £19,000 to £76,500, median £27,270, with three live as we write. Nationally the running order is fixed: the three-door whale-tail cars and the RS500s lead, the Sapphire saloons follow at a distance, and every serious bid is really a bid on documentation. This is the most faked fast Ford of them all, and the market knows it.
What to pay
£19,000 to the mid twenties buys Sapphire-era cars and three-doors with stories: higher mileage, older restorations, gaps in the file. Around our £27,270 median sits the honest, usable Cosworth with its history intact. From there to the £76,500 ceiling the money is chasing the three-door cars and the limited-run specials in original, verified order, and the national market has shown it will keep paying for the best of them.
What goes wrong
Provenance first, metal second. Verify the VIN, the chassis stampings and the engine number against the paperwork before bidding; replicas built on ordinary Sierra shells are common enough that an unverified car should be priced as one. The shells rot in the usual Sierra places: rear arches, sills, inner wings and around the sunroof aperture. The YB engine itself is a strength: hugely tunable, thoroughly understood, and supported by a parts and specialist scene as complete as any engine of its era; the risk is past abuse, since many ran big boost long before they were collectable.
Our view
Buy the paperwork and the shell; the YB can always be rebuilt, but originality cannot. A documented, standard three-door is the keeper, and the specialist support means these will still be running when subtler classics have retired. An unverified Cosworth is a replica with better luck, and should be bid accordingly.
