In the 1980s, battles raged between Germany's chief power brokers to try to win the war of the autobahn. How did they compare then, and which is the best modern classic today?
► Finding out which is the best 1980s grand tourer
► It’s an all-German battle to find the king of the autobahn
► Can V8 muscle beat a highly-tuned straight-six?
Let's start by thanking West German road transport policy in the 1970s and '80s, which did more than anything else to shape the cars we're celebrating.
That's because, while the first autobahns had been constructed before World War II, it was only as the capitalist part of the country became increasingly prosperous in the '60s that the network expanded. In 1970, there were 2500 miles of autobahn; by 1980, that had risen to 4530, and by 1990 - when Germany was reunited - there were 5500 miles. And what were the increasingly rich and hurried Germans going to drive on this splendid, and mostly derestricted motorway network? Cars like these, of course.
By the mid-1970s, the top German manufacturers found themselves in the middle of an almighty power battle, trying to create the ultimate high-speed coupes. Faster and more affordable than the hand-built Italian GTs from Lamborghini, Maserati and Ferrari that dominated this market sector, these cars were designed to operate safely at the sort of speeds that would have shaken their bespoke supercar rivals to pieces.
Although built for German tastes, they became hugely popular here in the UK, too. These bruisers from Porsche, BMW and Mercedes-Benz all gave you the opportunity to flaunt your wealth as the country powered through the '80s - and consumption didn't get much more conspicuous than a gold Mercedes SEC. They make a strong case for themselves today, too.
Mercedes-Benz 560SEC
The bright gold Mercedes-Benz 560SEC initially steals the show - it's big, imposing, and very stylish. It also has quite a history, which might explain why it's now part of Mercedes-Benz UK's heritage fleet. Past owners include art critic Brian Sewell and, before him, Nigel Mansell.
Given its looming and unsporting presence, your expectations are that it's going to be a less engaging drive than the Porsche 928 or BMW M635 CSi. Initially your expectations are met - imagine driving a very comfortable sofa that can throw you effortlessly towards the horizon, and you have some idea of how the mighty Mercedes-Benz goes down the road.
Everything about it seems designed to make life as easy as possible, from electrically adjustable seats through to the deferential way the standard automatic gearbox shuffles its ratios. The 5.5-litre engine came only three years after the launch of the original C126 coupe, and as well as a power and torque boost over the earlier 500 SEC, it had a standard limited-slip differential to help it deliver its 295bhp and 317lb ft of torque safely to the road surface.
Although you can hustle the 560SEC along at quite a pace if the mood takes you, it's a cruiser rather than a bruiser. It has finger-light power steering, generously boosted brakes and a cabin that's calm even at autobahn cruising speeds. Back in 1989 its biggest rival was probably a Learjet.
But the SEC has a party trick up its sleeve. Select Sport mode on the floor-mounted gear shifter and it'll accelerate like a rocket. There's almost no hesitation as it hurls forward in a manner more sudden than you expect.
The range-topping C126 coupe was a technical tour de force in its day, pioneering many systems that have become ubiquitous in more mainstream cars since it was launched. For us, the highlight of the SEC experience has to be the automatic seatbelt winder - you'll never get tired of surprising first-time passengers with a robot arm that politely offers them their belt.
BMW M635 CSi
This BMW M635i CSi is one of the very rare UK-only Motorsport editions, meaning it was loaded with every available option. In contrast to the Mercedes-Benz and Porsche's timeless lines, the M635 CSi looks about as '80s as it's possible to get without wearing a shoulder-padded jacket and clutching a Filofax in each hand.
The 6 Series (E24) was an extremely long-lived car, on sale from 1976 to '89, but the ultra-clean lines of the early versions were lost beneath some very muscular bodykit cladding as time went on. By the standards of the day it was a tech-laden car, with a multi-function trip computer and - on this car - even a period British Telecom carphone. The straight-six fires into life with a purposeful snarl that leaves little doubt of the M635i's motorsport pedigree.
The straight-six can't match the grunt of the Porsche's V8, although 282bhp was a remarkable output for a 3.5-litre of the period. It's far keener to rev, pulling enthusiastically and delivering a forceful shove that certainly doesn't feel as sharp as we suspect it should - new linkage bushes would probably tighten it up - and the clutch pedal is heavy.
However, it steers and changes direction with markedly more enthusiasm than the Mercedes-Benz. The rack isn't ultra-accurate, but it delivers strong front-end responses alongside excellent feedback, with the rear tyres happy to play along to the throttle pedal. Even in the wet it feels progressive rather than snappy - alive and always exciting.
Porsche 928 S4
The Porsche 928 is a 1991 S4 model, meaning it's powered by the later 32-valve 5.0-litre V8 mounted beneath the long bonnet that pumps out 316bhp. Like most 928s this sends drive rearwards via a four-speed Mercedes-Benz sourced automatic gearbox in place of the standard five-speed transaxle.
In comparison with the oh-so 1980s 560SEC, the sleek lines of the 928 still look modern from almost every angle - remarkable when you consider it first appeared in 1977.
The cabin is a comfortable place to spend serious time, with pliant seats, clear instrumentation and none of the cluttered ergonomics of contemporary 911s. Settle down into the interior and you're fully laid back - it's more a capsule to the horizon than a car cockpit.
The big V8 is still the 928's defining feature, with an abundance of torque giving it solid urge pretty much regardless of engine speed. But it's more than just a low-down slugger, with a sonorous enthusiasm for exploring the top half of its rev counter when called upon to do so - it's definitely the quickest in the group. It sounds great as well, like a big, comfortable Can Am racer.
But the gaps between the ratios of the autobox make themselves felt. Only 15% of later 928s were specified with the five-speed manual transaxle, but they're definitely worth looking out for. However, with some London dealers asking for more than £60,000 for low-mileage manual examples, you'll need to look hard and wide to land one of these for a reasonable price.
Your first introduction to the 928's steering may be disappointing - at low speeds it's heavy to the point of being obstinate. But that's a false impression - get on to sweeping A-roads, increase your pace, and it all starts to click. Pushing on and strong-arming the 928 through long sweepers with forceful but smooth inputs is the way to handle it, revelling in the linear responses and the vast reserves of grip.
Then when you come to a straight, boot the throttle and relish that V8 roar. Even with an automatic gearbox, you'll feel properly involved, with instant throttle response, and a V8 soundtrack unleashed straight from Beelzebub's basement. This is not a car for the faint of heart or small of bicep - and it's all the better for it.
What’s the best 1980s grand tourer? The CCfS verdict
The Porsche is definitely the design icon in this pack, but it's also curiously hard to warm to. It's a tool for going very, very quickly, but it's a bit devoid of soul in this company - unless you're truly hammering it, that is. The M635 CSi feels like a car that's on the cusp of greatness. Usable and enormous fun to drive, it deserves to be treated like the true 'M' car it is, and there's the sense that it's been overlooked for too long.
Yet the SEC is a compelling and multi-talented offering, too, especially now values are rising.
As modern classics, they all have appeal. The 928 S4 is rowdy and brimming with attitude, while the M635 CSi's dynamic excellence makes it most special. But the SEC is the prime modern classic by a narrow margin - it's simply more drivable for more of the time. That it's now beginning to appreciate strongly is the icing on the cake.
