BMW M3 (E30)

Start with identity, paperwork and originality. For the BMW M3 (E30), 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 panels, factory paint, matching S14 engine, Motorsport cloth/leather, books and Evo specification are major drivers.

The S14 is robust but expensive to rebuild; timing-chain, head, throttle-body and over-rev history matter. A proper pre-purchase inspection should include cold start behaviour, leak-down or compression testing where appropriate, diagnostic scans on modern cars, underbody photography, suspension pick-up point checks, brake condition and a road test long enough to reveal heat-related faults. Deferred maintenance is usually more expensive than buying the better car.

Use a paint-depth gauge, lift access and a specialist who knows the model's factory seams. Collector value is heavily affected by structural repairs, poor paintwork, corrosion, incorrect panels and missing factory trim. Cosmetic restoration can be acceptable when documented; hidden accident repair should be priced severely.

Evolution II, Sport Evolution and original left-hand-drive coupes lead the market; buy on shell condition and originality. Specification, colour, transmission and limited-production variants can move values dramatically. Buy the best-documented car in the most desirable specification you can justify, rather than a tired example of a rarer derivative that will require years of corrective work.