And saloon versus ‘saloon’ (the Panamera is actually more like a big hatchback), the Porsche’s more accessible boot might well more than make up for in cargo practicality what it gives up to the BMW in terms of second-row space. Here, maybe bigger doesn’t necessarily also mean more usable.
The Panamera certainly has the more convincing, consistently expensive-feeling, luxury-grade interior – and the lower-couched, though slightly smaller, driver’s seat. Its operating concept is less weighed down by the onslaught of mode selection than the M5’s.
It offers simpler, easier routes to switch off the ADAS features that are most likely to irk. Settling into the Porsche’s driver’s seat, you know instinctively what its priorities are and you needn’t take long tuning the car to suit your own mood and journey.
In the BMW – with a smorgasbord of options to puzzle through (M mode, powertrain mode, damping mode, steering mode, gearbox setting, driveline torque distribution mode, stability control level… the list goes on) – you could spend days experimenting, just as I did, and still feel little the wiser.
The final round
These winding, steep, bumpy and variously narrow mountain roads are a tough test of a big, fast saloon car.
But they waste no time at all in revealing what ‘good’ feels like when it comes to keeping one within the borders of its lane and primed for the moment when the vista opens in front of you, and you can feel – for a few, eye-opening seconds, at least – what 700 electrically assisted horsepower feels like.
The horses aren’t really what you notice, though. Rather, the influence of these cars’ electric motors is to give each of them Herculean, cliff-edge torque.
So – much as you might indulge yourself with them anyway, just because – three downshifts and a blast to the redline just aren’t required to make these cars explode forwards. One casual flick of your left index finger and a deep squeeze of your right foot will do it.