The nine rarest things in the Bonhams Festival of Speed sale

1. 2022 Bussink GT S Speedlegend (one of one)

Valued at £550,000-£750,000

You want something unique? You need this. It’s clearly a Mercedes, but a complete one-off that reinterprets the AMG GT convertible as a speedster. At first sight the transformation seems mostly to involve replacing the windscreen and side windows with something called the Speedwindow and adding a version of a halo.

The design – dubbed Speedbow – is certainly eye-catching. The 180-degree vestigial screen may or may not keep the bugs out of your teeth at the very high speeds the Speedlegend is capable of, but no matter, because the car comes with a matching pair of helmets. 

Underneath it's an AMG GT S, with a hand-built 515PS (384kW) V8 engine, seven-speed dual-clutch gearbox incorporated into a rear transaxle, and an electronically controlled limited-slip differential. It’s the creation of car collector and enthusiast Ronald A Bussink whose influence with Daimler is such that he got the people responsible for the Three-Pointed Star’s DTM racers and Black Series models to build it for him. A very exotic one-off.

2. 1925 Bugatti wristwatch (one of 20)

Valued at £50,000-£80,000

Horseshoe-shaped case, red logo at 12 o’clock – it’s obvious which car company is behind this Art Deco gem. Ettore Bugatti commissioned Swiss watchmakers Mido to make a limited run of Bugatti watches which he gave as gifts to racing drivers like René Dreyfus, Rudolf Caracciola and Louis Chiron. 

Bugatti also handed them out to senior staff, including the general manager of Bugatti Cars in the UK, Colonel Sorel. And it is the colonel’s watch that Bonhams will be selling at Goodwood: a 14-carat gold Mido for Bugatti manual-wind wristwatch produced in 1925 as one of 54 watches of which it is thought just 20 survive. Will there be a Veyron or Chiron owner able to resist it?

3. 1969 Unipower GT Competition (one of 40)

Valued at £50,000-£70,000

The Unipower is a road racing rarity from the 1960s, little known today, but a giant-killer on the track in period. You could expect as much, for the pretty mid-engined coupe was conceived, designed and built by racers, witness its tubular space-frame construction, fully independent suspension and all-up weight of just 545kg. Even the pretty fibreglass body had a racing connection: it was designed by Ford GT40 stylist Ron Bradshaw.

A total of 73 Unipower GTs were made between 1966 and ’70, most as road cars with luxury interiors courtesy of Wood & Picket. Only 40 cars are thought to have survived. This road-registered example has recently been rebuilt to race-ready standard by RJN Motorsport, and it comes with a race-spec Cooper S engine and all the FIA paperwork needed to be eligible for the great road rallies, and even the Le Mans Classic.

4. 2007 Koenigsegg CCGT (one of one)

Valued at £3,000,000-£4,000,000

Any Koenigsegg is exclusive, but this one is unique, a one-off built to take the Swedish supercar brand endurance racing in the GT1 class. It never got to race; two months into its shake-down tests it was rendered obsolete overnight when the FIA changed the class regs. Thus we were deprived of what was in the early Noughties the manufacturer of the world’s fastest car, destroyer of the McLaren F1, taking on allcomers at Le Mans. To say that is a shame is putting it mildly. 

At least someone – someone with upwards of £3 million to spend that is – will have the pleasure of driving this one and only CCGT with its carbon-fibre/honeycomb chassis and normally-aspirated 5.0-litre 32-valve V8 putting out (a restricted) 600PS (447kW). It weighs in at under a tonne and boasts 600kg of downforce. The car has barely been driven since those shakedown tests 16 years ago.

5. 1989 BMW Z1 Alpina (one of 66)

Valued at £80,000-£100,000

This is number four of the 66 Z1s converted to Alpina spec as a final hurrah for BMW’s quirky (drop-down doors anyone?) if underrated sportscar of the 1980s. It could in fact be the only Alpina Z1 in the UK since it is unique among the 66 for being converted here, by BMW dealer Sytner. The rest were converted in the Alpina factory, with half going to Japan and most of the rest staying in Germany. 

The limited-edition roadster got the normal Alpina treatment: a mild power hike to 200PS (149kW), new exhaust, tweaked suspension, upgraded limited-slip diff, a three-spoke Momo steering wheel and lots of familiar Alpina badgework. A left hooker, the car has known history and has covered just 8,100 miles from new.

6. 1971 Trident Venturer (one of 225)

Valued at £18,000-£25,000

Aficionados of obscure British sportscars from the ‘60s queue here.  So what is this very yellow, quite handsome coupe? The Trident Venturer was a development of the first Trident, the Clipper, which started life as a Trevor Fiore design for TVR. TVR was having one of its many financial meltdowns at the time and in no position to do anything with it. The project was picked up instead by one of its dealers in Ipswich. 

Trident Cars was born and between 1967 and 1978 225 cars were produced. The Venturer was its star turn: it featured a lengthened Triumph TR6 chassis, independent suspension all round and power courtesy of Ford’s 3.0-litre Essex V6. There wouldn’t be many Trident survivors these days, let alone one like this well cared-for example whose previous owner cherished it for more than 30 years.

7. 2009 Alfa Romeo 8C Spider (one of 500)

Valued at £195,000-£245,000

Far and away Alfa’s best supercar for eons, the 8C was concept car turned limited-production model and a car acclaimed for its gorgeous, heritage-inspired looks and Ferrari-built V8 engine. Alfa pledged to make no more than 500 coupes, and did, but then added another 500 8Cs in the shapely form of the Spider like the car you see here.

To go with the 450PS (336kW) V8 from Maranello was double wishbone suspension from Maserati, and Maserati was also responsible for its final assembly in Modena. The result was more than just a pretty face with 0-62mph in 4.2 seconds and a top speed north of 180mph. Over the coupe, the Spider got carbon ceramic brakes as standard, one reason it cost so much more than the tintop when new: £175,000 plus options. And this car is not short of options, right down to its fitted luggage. That makes it a rare one, as does its unique-in-the-UK magnesium grey paint.

8. 1969 AC 428 manual (one of six)

Valued at £90,000-£130,000 

Think AC Cobra on a lengthened chassis and wearing sophisticated Italian clothes. Thanks to that fastback Carrozzeria Frua coachwork, and a mighty 428 cubic inch (hence the name) Ford V8 from the Galaxie in the nose, the AC 428 luxury GT was big news in the 1960s. 

Alas a price north of what Aston Martin was asking for a DB6 held the 428 back. Only around 51 coupes were ever made, with 40 of them thought to survive. This one is rarer still thanks to its manual gearbox, fitted to just six cars. Despite the 428’s rarity, there is in fact a second example, an automatic, in the Festival of Speed sale, with a guide price of £60,000-£90,000. 

9. 2015 Lagonda Taraf (one of 120)

Valued at £150,000-£250,000 

The Taraf, Aston Martin’s most recent attempt to revive the Lagonda name, was all about exclusivity. The hand-built limo cost a million dollars when new and was aimed primarily at the Middle East market where most of the 120 made were sold, including this one. The Taraf was based on a long-wheelbase version of the DB9’s VH Gen3 platform, with the extra cabin space all going into rear legroom. The cool looks were matched by 195mph performance thanks to Aston's familiar 6.0-litre V12.

The car Bonhams will be offering at the Festival of Speed, in Platinum White with Spicy Red leather, has been part of a private collection, has been driven just 75 miles in eight years and, says Bonhams, may require recommissioning. It also comes with a very wide price range, no doubt encouraged by the sale of another Taraf by Bonhams at its Bonmont auction in Switzerland early in June. That car shot past its estimate and eventually sold for the equivalent of £304,000. Valued at £150,000, this one at the Festival of Speed could be a rare steal – and it is being sold with no reserve price, so you never know...

See more from the Bonhams Festival of Speed sale here.