High and Mighty 23.04.2008

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Can the ultimate sporting SUV really replace a fast wagon? We pitch Porsche’s Cayenne GTS against BMW’s M5 Touring to find out...

 Regardless of how many years you spend testing cars, nor how expensive or cheap, fast or slow they may be, sooner or later every last one of them will introduce you to a genuinely new experience. It might be something big but foreseen, such as watching a dial on the dash of a Bugatti Veyron tell you that you’re currently being cannoned across the surface of the planet by 1001bhp, or something small but totally unexpected, such as discovering how remarkably well a new Smart ForTwo copes with snow. With the Porsche Cayenne GTS it was going to collect my daughters from school and realising as I neared the gates that I couldn’t go through with it. I knew that parking it around the corner would result in me and my children getting wet, but compared with other parents concluding that I actually chose to go about the place in a bronze Cayenne with a bi-plane rear spoiler and 21-inch rims, a thorough soaking seemed infinitely preferable. It was then, more than at any time during the most formal execution of this test, that I wished I was driving the BMW M5 Touring. The M5 is not a great-looking car, even when not wearing muddy maroon paintwork, but nor is it the kind that makes you want to run and hide. It is, in short, a car you can turn up in. We brought them together to answer the very simple question posed by the Cayenne’s positioning as, if not the fastest, then certainly the most sporting of its range and, by dint of the shield of Stuttgart on its nose, therefore the most sporting SUV you can buy: could it stand comparison to the most sporting ‘conventional’ load carrier? Which is where the M5 comes in. Seems a foregone conclusion, doesn’t it? BMW’s 10 cylinders versus Porsche’s eight. M5’s seven speeds versus Cayenne’s six. Touring’s 507bhp versus GTS’s 405bhp.

Given that the BMW also costs £67,725 compared with the almost-modest £54,350 asked for the Porsche, you might even wonder what they’re doing occupying the same pages. Yet the gap between them is not what it may seem. For a start, when you’ve added 10 grand or so to the Cayenne’s price for all the goodies that are standard on the M5 (cruise control, bi-xenons, navigation, full sunroof, CD changer, multi-function wheel, auto boot closing and bum warmers are just the ones I spotted), plus the automatic gearbox (without which I suspect the GTS will depreciate faster than if you drove it into a brick wall), their prices are remarkably similar. Second, the Porsche is, well, a Porsche and no respecter of evidence as circumstantial as mere statistics. And so it proves. The key to understanding the Cayenne GTS is that while its engine suggests a close relationship to the Cayenne S (better breathing ensures an extra 20bhp for the GTS), and while its bodywork apes that of the Cayenne Turbo, its character is unlike either. By linking its PASM adaptive damping system to coil springs for the first time in any Cayenne, dropping the suspension by 24mm, shortening the final drive and bolting on a sports exhaust, Porsche is creating a car that, however absurd the comparison may sound, is to the Cayenne S and Turbo what the 911 GT3 is to the Carrera S and Turbo. Driving it fast through the Welsh borders is like watching a mate’s clearly overweight dad suddenly execute a complex and flawless gymnastics routine around his rather small sitting room. For a car weighing 2225kg, its poise under pressure goes straight past impressive and lodges somewhere in the frankly rather weird. Something this high and heavy has no business being so agile. Stranger still, the manual gearbox may have a calamitous effect on residuals but it actually suits the car rather well. The shift quality, clutch weight and gear ratios are all as delightfully judged as you’d expect from any Porsche, even one that weighs the same as a white rhinoceros. The engine is interesting, too. The direct-injection, 4.8-litre V8 seems little different on paper to the engine fitted to the Cayenne S; power is up 20bhp but what are 20 extra horses when there’s 2.25 tonnes of car for them to tow, without a single pound foot of extra torque to share between them? Yet combined with the rasping exhaust and short gears, it creates the impression – be it illusory or real – that the GTS is a properly quick car, something I’ve never thought of an S. Still, you’d expect introducing it to an M5 Touring to be more than enough to dampen its ardour. But at least at first, they seem surprisingly well matched, largely because the Porsche’s performance is so much more accessible than that of the BMW. They develop similar amounts of torque (369lb ft for the Porsche, 384lb ft for the BMW), but while the M5 insists that you buzz the engine all the way to 6100rpm to reach it, the Porsche’s is all there down at 3500rpm. So while the BMW driver ponders just how many tugs of the gearshift paddle are going to be required before the desired response is gained, the Cayenne driver has already hit the pedal and gone. Plan your attack carefully, rev the M5 past 8000rpm and so long as there is traction available (never an issue in the Cayenne) it will drive away from the Porsche quite quickly. But it requires much more forethought and effort than the Cayenne will ever ask of you. But the rewards are clear and significant. Its badge may not be so mighty but this BMW is a much better car to drive. The critical difference is you don’t always feel the need to qualify your judgements of the M5 as you do with the Porsche. The Cayenne is only outstanding in its abilities ‘for a 2.25-tonne SUV’. You never feel think how good is the BMW for a 1.95-tonne estate; you just think how bloody good it is. Period. There are dedicated sports cars weighing hundred of kilos less that are dramatically less well balanced and elegant in their movements than this – and I’d include the sometimes-twitchy M3 in that list. It doesn’t matter if you’re keeping it neat, trimming your apexes down to feeler gauge levels of precision, or discovering just how absurd are the yaw angles it will tolerate while still heading in your intended direction; the Touring does it all as if it were the most natural thing in the world. And while an Audi RS6 may be a quicker, more capable all-rounder, it can’t interact with its driver like this. Nor can the Cayenne, whichever setting you choose for its electronically controlled suspension. The M5’s big weakness is its gearbox. A semi-automatic, paddle-shift transmission with driver-programmable mapping might sound like heaven at your fingertips but the reality is that a humble stick shift like that of the Porsche does the job a whole lot better. If you’re driving as fast as you possibly can it works well enough, but for the rest of the time it engages gears sufficiently coarsely to reflect badly on your driving and to make you reflect on the wisdom of buying the car. But you shouldn’t, for the perfect car has yet to be invented and if you are a seriously appreciative driver with this kind of money to spend on one car which must also serve as a family holdall, I know of none better than this. Of course the Cayenne has its advantages, but they’re not where you might expect. There’s no more room in the back and the boot is only slightly bigger than that in the M5, seats up or down. It is true that the Cayenne does have a kind of impervious quality, missing from the M5, that would tempt you out onto roads which would keep you resolutely by the fire were the BMW your only option, but whether that’s a good thing or not is a different matter. If conditions are too bad for a modern two-wheel-drive car with state-of-the-art traction and stability control systems, you could argue that conditions were too bad full stop. I would. And, in addition to being a quicker, better car to drive, the M5 is also quieter and more comfortable over long distances than the Cayenne. I have no doubt that the Porsche Cayenne GTS is the best-driving SUV that money can buy, but what this test has shown is that even the wizards of Weissach cannot turn raw material as unprepossessing as a sky-high, two-tonne off-roader into something that, dynamically, can hold a candle to a properly developed but utterly conventional estate. If you have a genuine need for such a car – perhaps because you have things to tow or because you live at the end of a long and muddy track – it comes with my recommendation. If not, spare yourself the old-fashioned looks at the school gates and get yourself an M5 Touring. It’s not just the best-driving estate car you can buy; of all the high-performance load carriers I’ve driven, it’s the one I would choose.