Centro Stile and Zagato — the 'Il Mostro' Alfa Romeo, a fixed-production wedge-bodied 3.0 V6 coupe.
Built between 1989 and 1991 by Zagato in collaboration with Alfa Romeo's Centro Stile, the SZ (codename ES-30) combined the floorpan and 3.0-litre 75 V6 (210 bhp) with a fixed-production composite body. Production was capped at 1,036 coupes, all in red with a tan interior, with the open RZ following in 1992–1994.
The car is known internationally as 'Il Mostro' — the monster — for its blocky, slab-sided silhouette and triple-headlight nose.
Fixed-production, Zagato-built Alfa Romeo using one of the great Busso V6s; recognised collector status.
| Variant | Years | Production | Notes |
|---|---|---|---|
| SZ Coupe | 1989–1991 | 1,036 | Fixed-production coupe. |
| RZ Roadster | 1992–1994 | 278 | Convertible derivative; significantly rarer. |
The models below represent the most significant limited and special edition variants — factory-produced cars that command meaningful premiums over standard examples and warrant specific attention from serious collectors.
Start with identity, paperwork and originality. For the Alfa Romeo SZ (ES-30), the strongest cars have continuous ownership history, matching numbers where applicable, original books and tools, factory build documentation and evidence of work by manufacturer-approved specialists. Original paint, matching numbers, Alfa Romeo Historic / Italian register documentation.
Busso 3.0 V6 is robust; cambelt service is critical and should be no more than three years old regardless of mileage. A proper pre-purchase inspection includes cold-start behaviour, ECU diagnostics and fault-code history (where applicable), leak-down or compression testing, underbody photography, suspension and chassis inspection, brake condition and a long enough road test to expose heat-related faults. Deferred maintenance on a car of this class is almost always more expensive than buying a better-sorted example.
Use a paint-depth gauge, lift access and a specialist familiar with the model's factory panel gaps and finish standards. Collector value is dramatically affected by structural repairs, refinished panels, poor paintwork and missing factory trim or option content. Documented cosmetic refresh is acceptable; concealed accident or fire damage must be priced severely.
Original chassis number from documented Italian or European delivery, untouched composite body and full Alfa Romeo Historic registration. Specification, colour, options and limited-build variants move values significantly. Buy the best-documented example in the most desirable specification you can justify, rather than a tired example of a rarer derivative that will need years of corrective work.
| Date | Auction | Car | Mileage | Result |
|---|---|---|---|---|
| 2026-05-21 | Collecting Cars Online | 1992 SZ | — | €48,500 Sold |
| 2025-11-08 | Iconic Auctioneers The Iconic Sale at the NEC, Lot 253 | 1991 SZ | — | £65,250 Sold |
| 2025-02-06 | Bonhams The Grand Palais Historique, Paris, Lot 110 | 1991 SZ | — | €103,500 Sold |
| 2024-01-31 | RM Sotheby's Paris, Lot 106 | 1991 SZ | — | €69,000 Sold |
| 2023-11-11 | Iconic Auctioneers The NEC Classic Motor Show Sale, Lot 239 | 1990 SZ | — | £58,350 Sold |
| 2023-02-01 | RM Sotheby's Paris, Lot 170 | 1992 SZ | — | €98,900 Sold |
Fixed production, Zagato build and Busso V6 underpin firm long-term demand.
Our view, not advice. This section is Car Collector International's editorial judgement on where this model sits in the collector market, based on the production, specification and market data set out in this guide. It is not a recommendation to buy or sell and it is not investment advice. Values can fall as well as rise.
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The valuation figures in this guide are for research purposes only and do not constitute financial or investment advice. See our full disclaimer.
