Something’s not right. Every short straight we encounter prompts the flat-six engine into another virtuoso aria as it heads towards the 7000rpm red line. But the picture is skewed. The problem isn’t the sound, but where it’s coming from. Although this water-cooled, horizontally opposed six-pot sounds every cubic inch like an ultra-refined 911, it sits ahead instead of slung out over my shoulder.

This is Subaru’s Legacy Spec B, the performance flagship of its most Euro-friendly model. A big Impreza it is not, and nor does Subaru want it to be. The Legacy is looking to tempt those wallets whose contents would normally be Munich-bound. Subaru has the BMW 3-series in its sights.

Impossible? Maybe not. We all know Subaru’s performance credentials and when Autocar road-tested the 2.5-litre Legacy we were impressed. The Legacy eschews its little brother’s bespoilered arrogance, relying on subtle detailing to mark out its quickest version. There’s a boot spoiler, chrome sill flashes, beefy bumpers, and 18in alloy wheels.

Unusually for a range-topper, the Spec B offers no added power. Instead, extra pace comes from a revised Impreza STi six-speed manual transmission in place of the current 3.0 R’s auto. And it works. The 0-60mph dash is cut by 1.8sec to 6.6sec (6.5sec for the saloon). The ’box isn’t as notchy as the Impreza’s, but despite all of Subaru’s efforts a fair amount of driveline vibration still arrives through the gearstick.