Iain Banks

Right. I think I’ve got it. It’s about switches, their nature and evolution. Harpsichords and DX7s enter into it, but we’ll come back to that. First off – almost as an initial disclaimer – yes, this is a truly great machine, a startlingly and consistently fast car. A compact, muscular gem of an engine wrapped in a brilliantly machined, fabulously composed, yet still malleable setting. Which only makes the faults stand out more. I’d nominate three: one trivial but annoying, one more fundamental that can be coped with given an adjustment to the driver’s style, and one deeper, more disturbing flaw that you could miss completely and which some people will regard as a positive advantage.

This is a comparison of the old and new BMW M5s. I have one of the old ones, bought new in January 2001, currently with just over 33,000 miles on the clock.

This is a car I am very at home in, and a car that is entirely capable of an almost self-deprecating normalcy. A car that’s docilely gone supermarket shopping, carried ageing parents with nary a complaint and many a purr of praise. It’s towed boats, pootled round cities, villages and far-flung Western Isles, hummed the motorways from Fife to Kent and back comfortably over 24 hours, jinked gingerly along sheep-strewn single tracks and – at last let loose – pelted, swung, darted and just plain zapped along some of the best roads in Britain, maybe in Europe; the long, open, sweeping, mostly empty, generally well-surfaced and not too often awash A-roads of the north and west of Scotland.

Forget the disarmingly compliant ride that draws unexpected and even (if you were taking this four-seat supercar stuff particularly seriously) not entirely welcome compliments from elderly relatives regarding how ‘nice’ the car is and how ‘comfortable’ the ride. Disregard the pussycat performance that results as long as only the first few centimetres of throttle-travel are pressed into play. Fie upon the sheer honed efficiency and calm user-friendliness of what was the world’s best medium/large four-door saloon. Just show the beast the wide open road and a set of bendy bits – preferably on a slope for added fun – stir the ‘box, plant the right pedal, listen to that V8’s sudden snarl and get whumped back into the chair grinning like a loon while the immediate landscape goes Stargate.

Then it is like driving a sports car; a very good sports car, and one that was, to the end of its model life, still seeing off the upstart best that the Mercedes, Audi and Jaguar engineers could throw at it. I traded in a year-old Carrera 4 for this comfy big saloon, and got a better, quicker, more accomplished car.

A lot for the new model to live up to, then.

For the purposes of real-time comparison on truly spiffing roads, both cars had to be got to the village of Glenfinnan, in the Western Highlands. So, on consecutive days, each was driven up my usual route north, a collection of A, B and off-alphabet roads and wrigglies, staying away from the efficient but boring A9 until the last minute, then joining just at the start of the road’s longest dual carriageway section before the big straights and fun bends start again past Dalwhinnie. The old car is just a joy; supremely confidence-inspiring, burrily-throated, endlessly thrilling...but then, as I say, we’re like old friends, and so it should be.

The next day, the new M5 feels palpably bigger, firmer and more staccato. I’d decided before I left home I’d leave the power setting on 400bhp to provide a more direct comparison with the old car, and let the gearbox do its own shifting. The first resolution lasted all the way to Fort William, with just 15 miles to go. The second bit the dust barely 20 minutes out from home, near Gleneagles. Fully auto gearboxes are a relief in jams and cities, but kind of beside the point in this sort of car on these kinds of roads. Time to flip some paddles.

Well. The car is beefy but the change is jerky. I read up on the blighter the night before and know how to switch between the different gear-changing programmes, but it seems to be impossible to upshift without doing the head-nodding thing. In fact, it feels like the car’s bogging down on every change up, no matter what I do. Eventually I work out you have to lift-off just as you hit the paddle, and things became smoother again. Changing down is far more fun; the electronics blip the throttle during even modestly spirited downshifts, squeezing a highly satisfying rasp out of the glorious V10.

I’ve enlisted my pal Les for the following day. We drive from Glenfinnan across to Grantown-on-Spey, head north to Nairn and then on to Garve for lunch and an exchange of notes. We both hate the indicator stalk, which seems to have been fixed when it wasn’t broken; too often it won’t cancel, then, when you try to cancel it manually, it indicates the opposite direction. Etcetera. And etcetera again. Not to hilarious effect. To bloody annoying effect. Plus it’s too easily hit when aiming for the downchange paddle. That’s the relatively trivial fault.

We are both deeply impressed by the head-up display. It makes instant, total sense. Immediately you think, every car should have this. I’d rather the rev-counter component – a sort of squished, vaguely fluted rainbow thing – better replicated the standard binnacle instrument, even if it had to look tipped-over to fit, but this is to quibble.

We love the rasp of the new car’s engine.

We also love the M-button on the steering wheel, which switches in the extra 100 horses and changes the car’s whole traction control and damper set-up to whatever’s been selected earlier (clicking on the extra hundred bhp is a total hoot, though you’d want to be careful with it in the wet, traction control or not).

The five-and-a-half-grand, fuller-than-full, full leather option contrives to appear plasticky in places and Les says the inside reminds him of a people carrier. I hate the new convex dash, preferring the old concave one. And I still like wood rather than brushed aluminium.

Neither of us likes the SMG gearbox, no matter how intelligent it is or how fast it claims to be. This is the more fundamental fault, though it’s still not what you’d call a deal-breaker. I’ve refined my lift-off technique to doing so just after clicking the right-hand paddle. Better, but not perfect, and it just doesn’t feel as smooth as a manual or as quick as it should, or even as smooth as a good conventional auto ‘box.

It occurred to me earlier that I was probably changing up too early – this five-litre V10, no heavier than the similarly-sized V8 in the old car, spins happily to 8,500rpm – so I have experimented with letting the revs climb into the orange section of the rev counter before upshifting, hoping this will sort out the bogging-down, head-nodding effect.

I choose a great long straight on the A835. Third to fourth ought to happen somewhere near the legal limit, oughtn’t it? I watch the revs on the head-up, flicking the right paddle when the orange section starts to illuminate. Check speed. Ninety-six bleedin’ miles per hour. A few more tries and the average settles at about ninety-two. And still there’s a head-nod, still a hesitation. Oh well. Back to lifting off.

Our route as taken us past the plump of ploughed fields smoking with vapour in the sunlight after sudden cloudbursts, towards and across the Kessock Bridge, arched grey against the steel firth, green fields and brown hills, all overshadowed by a great gun-metal skein of cloud to the west; towering, anvil headed. Further west, we head for Kyle and Skye between the peaks of Wester Ross and Strath Bran, then turn back south, through intervals of glittering blues and sullen grey drenchings that test the water-shedding abilities of even these well-cambered, prodigiously drained Highland roads. Both cars are stunningly good, both feel in their element, shrinking the coast-to-coast journey so that it seems over almost comically quickly, each shrugging off weather, darting past slower traffic, feeling poised and assured and staggeringly, intoxicatingly fast.

So why was the old car, a hundred bhp short and no lighter, more fun? It’s that gearbox, and those paddles. The problem is that the paddles are just switches, like the keys on a harpsichord or an old-fashioned synthesiser. Harpsichord strings are plucked; it’s an all-or-nothing action. A piano’s strings are hit, and the player has a choice regarding how hard or how soft they’re struck, as well as control over how long the note is held. Three-quarters of the attack, sustain, release and decay envelope is effectively fixed in the harpsichord and almost infinitely controllable in the piano, and it’s why the piano is so much more expressive than the earlier instrument.  Mind you, it’s also why harpsichord music sounds better in a car, unless you have a very quiet (ie, very expensive) car with a very good (ie, very expensive) hi-fi; in a harpsichord piece there are no truly quiet passages not to hear over the extraneous noises derived from just driving.

The first electronic synths, too, had keys that were basically just switches; binary on/off buttons. Nowadays, some of the best electronic keyboards have a full hammer-weighted action, and many have velocity sensitive keys with after-touch.

The DSG box needs something like this; a choice over how slow or fast the change is made, depending on whether the paddle is squeezed or flicked, specific to each change. No amount of preset programming can match that immediacy.

Or just have a manual ‘box, with all the control over gear selection speed and clutch take-up it gives you. You might take an extra five seconds to get round the ‘Ring compared to a similar car with the DSG gubbins, but it’ll be more fun. I guess I feel grateful to the new car for reminding me how much control one really has with a well-sorted manual ‘box and an accurately modulatable clutch mechanism. I intend to appreciate this controllability for as long as I can before the choice disappears in the future.

Lastly, though, a flaw that may or may not be a real fault at all, depending on your point of view.

It’s this: there is something genuinely too accommodating about the new M5. It’s too eager to please, too willing to be what you want it to be, not what it just damn well is. You can alter, mould, shape and customise so much about this car – and it will continue slavishly to anticipate your every driving need subsequently once you’ve trained it to do so – that it becomes Stepfordian. It’s so desperate to do just what you want it to do that you start to lose respect for it. You just want the car to be itself, and that’s precisely the last thing it seems to be able to offer.

What basis for a long-term relationship is that?

As I say, some people will think this character-sapping characteristic is just exactly and robustly what the management consultant ordered.

If it was possible, I’d take the old car with the new engine and the head-up display. It isn’t possible, of course, and the new machine is in almost every way, a measurably superior successor, but, in the switch, something really has been lost.