Second order saloons: BMW M550i vs Mercedes-AMG E53 Estate

You will know if you’re the sort of person who’d feel the need to constantly explain to friends why you went for a notionally subordinate performance car instead of an Mercedes-AMG E 63, BMW M5 or even an M3; and if you are, maybe this option isn’t for you. But all you really need to know is, with higher mileages, and the really varied, year-round pattern of usage that a ‘daily-driven’ car might see, an M550i really isn’t inferior to any of those cars. It is, in fact, probably the better-sorted, more composed road car in most everyday driving scenarios, having the compliant chassis tune to deal with bumpy B-roads and motorway alike, and never feeling firm or highly strung.

The M550i’s 4.4-litre turbo V8 – a motor closely related to the one you’ll find in an M5 Competition anyway – wants for absolutely nothing you’d ever be likely to miss during UK road driving. It’s got huge reserves of power and torque, a quietly enticing and cultured V8 exhaust note to compliment; and it’s a monstrously fast car.

Ride isolation and rolling refinement are very good, although perhaps slightly blunted by the BMW’s standard-fit runflat tyres. Steering feel is neutered just a little as you guide the car off-centre, for the same tyre-related reason, I suspect; the unyielding sidewalls of runflat tyres just don’t quite load up and flex in the way a conventional tyre would.

The 5-Series’ chassis is really well-balanced, though, and its body control can be adjusted from pillowy and absorbtive to closely tied down with the adjustable driver modes. So when you want it to feel like a mini-M5, the M550i xDrive can (although more like an old V8-powered ‘E39’, predictably, than any since). But it needn’t feel like that on a midnight return from the airport, or on the weekend family jaunt to visit Grandma, if you don’t want it to. This is, in short, a modern fast BMW like they used to be; one that, as a road car, simply offers more.

Mercedes-AMG’s E53 has a better all-round visibility and a less sunken driving position than the BMW. For interior ambience, it’s the more flashily luxurious and tech-laden car, too, thanks to its domineering side-by-side digital instrument screens, and all of the chrome trim and leather around the cabin. The BMW’s driving position is better, but the Mercedes’ is almost as comfortable and easier to access.

And here’s another surprise: to drive, the E53 actually has the sharper turn-in of the two cars. It has equally dependable mid-corner lateral grip, and the kind of any-weather traction that makes the modern performance cars work all year round. In outright terms, the E53 feels softer-sprung, though. It rolls harder and to slightly greater angles than the M550i, and it seems to rotate more slowly through the apex as it corners than the fundamentally better-poised 5-Series does, its throttle-on balance being that bit less sweet than the BMW’s also.

Then there’s the E53’s six-cylinder hybrid powertrain, which you’ll want to like for all sorts of reasons. In the end, though, you’ll probably have to concede that it isn’t nearly as convincing as the BMW’s wonderful V8. The AMG engine revs keenly and smoothly, as straight six engines famously can; although it doesn’t always sounds as great as it should. Don’t get me started on explaining how we can be pitting a Mercedes-AMG with a straight six engine against a BMW M car (of a kind) with a V8 in it. And yet, here we are. And for accessible torque the AMG’s electrified six-pot feels quite a long way adrift of the BMW’s mark, and its nine-speed gearbox isn’t quite as convincing as the BMW’s eight-speeder either in its capacity to ‘pick and stick’ with a well-chosen ratio either.

Does real-world touring economy make up the difference? Well, it wouldn’t for me. In mixed use, the M550i is a thirsty thing likely to average 25mpg at best – but, on the basis of what it did on loan with us, the E53 would likely only hit 28- to 30mpg itself.