BMW M4 vs Lexus RC F: fight!

A simple straight-line test is not the correct way to judge which is the better car here. I know that. But it is a lot of fun. And quite revealing. So the Lexus RC F lined up alongside the BMW M4, modes were fiddled with, traction settings chosen and when both drivers were happy, they set off.

And the BMW won. By a country mile. By the time the M4 reached 100mph, just 8.8secs after it set off, the Lexus was already getting on for two seconds adrift. Later, we did other metric stuff, and we found out that the BMW is much faster around a circuit, can pull more g and stop harder. To many people, this must mean it's a better car.

Pictures: Joe Windsor-Williams

This feature originally appeared in the March 2015 issue of Top Gear magazine.

But is speed alone the thrill? Do the extra g-forces the BMW driver experienced make the M4 that much more exciting than the slightly slower RC F? Of course not, even if it often seems that Nürburgring lap times are what is pushing car development. It's easy to measure these metrics, easy to absorb the nuggets of information they supply, easy to assume they're all that matters.

I know, they all claim that the move to turbocharging is about emissions, but behind that facade, I reckon there's a bunch of marketing engineers rubbing their hands at the prospect of easily liberated horsepower. So it's impossible to buy a naturally aspirated BMW M car any more, and with the arrival of the new C63, all AMGs are now forced-induction, too. No doubt the Merc does the numbers as effectively as the Beemer, too. Mercedes'll have done some measuring and made sure of that.

Yet Lexus, embracers of all things ecological, has managed to stick with a naturally aspirated V8. Albeit a relatively slow one. Japan must be too far away to feel the pressure of European competition. So does the Lexus, developed in isolation far away, and - let's face it - aimed at a more American audience, make up for its lack of outright speed with a dazzling chassis that makes you whoop with joy at the scent of a Dunsfold corner? Er, no.

It may have a lovely big V8, but Dunsfold isn't its natural habitat. The Lexus weighs a quarter of a tonne too much and feels baggy after the BMW, carrying a quarter-turn of understeer through the Follow Through. It has a TVD (Torque Vectoring Differential) system with an Expert mode that's meant to permit drifting, but when I tried it, it only permitted me to spin.

The RC F seemed permanently confused by Dunsfold. Even trailing the brakes into Second to Last failed to cure the understeer or improve the chassis balance - this is a big, thick, heavy car that isn't nearly as adjustable as it should be. It did do good skids, though. Expert mode may have been a dead loss, but if you fully disabled it and gave the back end the berries in a slow corner, the car would arc wide and sit there happily, puffy clouds billowing from the arches, while the astonishing steering lock - normally only considered a boon for parking - allowed the RC F to be rescued from oblique angles. That was fun. Apart from that, it was slow and didn't stop or grip that well. Not only mathematically this time. The inert brakes soon went from feeling meaty to feeling spongy, and the tyres struggled with all that weight.

Don't feel too sorry for it yet, because there are upsides to the Lexus that we'll come on to. Before we do, we need to discuss the BMW. Yes, at Dunsfold it trounced the Lexus in a straight line and went everywhere with more speed, determination and control. But, above all, it was sharper. The nose went where it was told, when it was told, and provided you didn't get carried away, the rear tyres would push it very effectively onwards.

But if you did get carried away, even only slightly, the BMW developed what we'll call a "traction issue". In short, it struggles to get its power down. A prod too far and, if you didn't have your wits about you, the M4 would no longer be facing the exit of the corner, but the entrance. In fact, sharp might not be quite the right word to describe the M4 on track - spiky and edgy are equally valid. In Sport Plus mode, the throttle response is savage, clever engine management keeping the turbo spinning so you don't get caught off-boost. It kicks very hard, is tricky to drive smoothly and easy to get wrong.

It's as if BMW were worried that the M4 would be perceived as a bit of a softie with the adoption of turbos, so decided to equip it with a scorpion's tail - jabby and poisonous. Of course, this also means it's a laugh on track, rarely pointing straight, and you can, of course, back all the settings off, and the BMW actually becomes more manageable.

However, on this evidence, the bald numbers seem to be proof of a better car. But the question is this: how much does track driving matter to you over and above road driving? You may do a couple of track days a year, but the other 363 days are all about road driving. And out there, it's a different matter. The BMW still has traction issues, and here they're less amusing. It can't get out of a junction without an orange light flashing. And the engine noise is rather forced, the double-clutch gearbox jerks the shifts unnecessarily and, bar some extra carbon, the cabin is that of a standard 3-Series. And why don't the top bars of the wing mirrors join up to the door?

It just feels a bit over-processed, too much garnish, a hint of pantomime. Ultimately, there's a suspicion that the M4 is acting the part of an M4, rather than actually being an M4.

Don't get me wrong: it's still good, but it seems slightly out of kilter, doesn't have the integrity or purity of purpose that made older M3s so enthralling. The engine is central to this - the M4 is missing the rasping yowl of a clean-breathing straight-six barrelling its way to 8,000rpm.

And a bombastic engine is one thing the Lexus does have in its favour. The Lexus V8 is all heart and soul and effort, it responds well, is a genuine pleasure to fire up in the mornings, is so honeyed on its way to the 7,000rpm limiter that it seems as if it could rev to 8, 9, 10,000rpm, even. It's deeply satisfying. And so's the rest of the car. The cabin is more coupe-ish than the M4's, with an interesting terraced dash (although the infotainment is hopeless), it's well planted with good traction and stability, more refined and relaxed, vigorous rather than vicious. I liked it on the road: it was burly, honest, endearing and surprisingly dextrous. Better than the BMW. Which, given the 363:2 road/track ratio, must make it the winner, right?

So nearly. If it'd been 300kg lighter, I think we'd have a different verdict here. The BMW wins, but it's a victory hollowed by the M4's strange imbalance - it's not as well rounded as it ought to be. Too much focus on the numbers, perhaps.