Power of 10, BMW M5 v Lamborghini Gallardo

Twelve used to be the magic number. Still
is for those of us with long memories. But while there remains something very special about driving a V12-engined car, the tortured howl of a modern F1 engine has fostered an unrivalled fascination for the V10, and endowed ten-cylinder road cars with a unique cachet. No wonder that despite it being almost a year since we first drove the BMW M5, and more than two since Lamborghini first handed us the keys to a Gallardo, both cars continue to hold us in their thrall.

Parked side-by-side, the M5 and Gallardo make an impressive if rather odd couple, but it's the incongruity that cements the spectacle. That it's the bulky German saloon and not the athletic Italian supercar that has the heftier punch and the (theoretically) greater v-max only serves to ladle a little lunacy over this already improbable, intriguing pair.

Spend enough time with either car and the V10's mystique leads even complete strangers to request that you pop the bonnet. Lift the lid on the M5 and, aside from the sheer size of the motor crammed into the engine bay, it's a bit of a disappointment. It's all too clinical: big, plastic shrouds hide all the interesting bits away, creating an air more suited to a domestic appliance than one of the mightiest normally aspirated production engines ever built.

The noise isn't that special either when you start it up: a dry, busy chatter, half-way between a big-capacity turbo-diesel and a petrol engine running a bit low on lubricant. A blip of the throttle hints at pleasures to come, but it still leaves you wondering where the passion and drama is hiding.

You only need look under the Gallardo's engine cover to find it. A lesson in the aesthetics of black crackle finish and crisp machining, the Lamborghini's V10 is what a proper engine should look like. Pipe runs, cables and hoses are proudly on display and add to the sense that this is a living, breathing machine that needs feeding with fluids and air to function.

Twist it into life and the Italian V10 clears its throat with an exuberant snort before finding a fast, blaring idle that hits you right in the guts. Of course, a supercar can get away with these kind of aural histrionics, in fact such a glorious cacophony at tickover is compulsory. And, while you don't expect the M5 to vibrate windowpanes at 50 paces, you can't help thinking BMW has missed a trick by neutering the first few moments of the M5 experience.

Cut to the fast, challenging moorland roads of Lancashire's Trough of Bowland, and the M5 finds its forum. The roads are more suited to an Impreza STi, but the BMW is pulverizingly quick, steam-rollering gradients and piling on speed with utter disdain. The engine has found its voice too, building to a uniquely strident, visceral wail as it pulls to 8000rpm and beyond. At full-chat the M5's V10 is fearsome.

Such raw aggression comes as quite a shock, especially after the sedate, refined manner in which the M5 dispatched the M6 motorway earlier in the day, but the speed and ferocity of the monster M Power saloon is a double-edged sword. Having Roger Green in the Gallardo up front is an excellent incentive, but as our speed increases and the road begins to duck and dive, you get an increasingly insistent feeling that while the V10's up for anything, there's massive momentum at work, and it takes far more out of the M5 than you'd think simply to stop it running away with itself.

While there's an impressive sense of grip and traction when driving the M5 in isolation, following in close company with the Lamborghini is a stark illustration of just how much restraint you have to practise in normal driving, and how little of the V10's 501bhp and 383lb ft you're able to use before cracks start showing in the M5's impressive dynamic facade. At what feels like 7/10ths the M5 has a reassuringly composed feel, but it needs to dig a lot deeper than that when Green squeezes on the Gallardo's throttle with a little more insistence, or pushes just that little bit harder and deeper into a corner on the brakes. Do so and the M5's limits suddenly don't feel so lofty.

Jumping out of the M5 and into the Gallardo is to step into another world. Stripped of the M5's space and well appointed but overwhelmingly normal interior, the Lamborghini is a much more intimate machine. Slung low and squeezed tight between door and transmission tunnel, you feel every buzz and tingle, while the added weight of the steering and the increased interaction of a manual transmission immediately define your role as that of driver rather than awed passenger.

Attacking the same stretch of road, Lamborghini leading, Green now following in the M5, it's easy to see how the Gallardo can toy with the BMW. Its engine, so vocal and energetic, summons greater low-rev and mid-range torque, something that feels all the more impressive in a car that weighs a third of a ton less than the M5.