All four of these cars are magnificent machines, conceived to devour miles with a minimum of effort, yet engage and entertain when mood demands it. However, least convincing in the supersaloon role, at least in this specification, is the Porsche. We debated whether to include a Panamera Turbo or Turbo S, but the £100K+ entry price ruled it out. The trouble is, true supersaloons need to be ultimates, and in this company the 400bhp Porsche felt out-gunned. The manual gearbox of this press car also, sadly, proved slightly cumbersome.
The XFR is a strange car. It’s a truly handsome machine, even in Constabulary White, but the interior and general detailing is a bit glitzy and cheap compared to the German brands. It has prodigious performance and a beautifully lissom feel on a raggedy road, but struggles to up its game to match the out-and-out performance and tight dynamics of the Benz and BMW. Ultimately greatness eludes it.
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Splitting the bi-turbo Germans initially felt impossible, but the M5 steadily and relentlessly asserted itself. In all areas – with the possible exception of steering feel – the M5 out-points the AMG. Crucially, its ability to subtly adapt and adjust its delivery from imperious motorway mile-eater to ballistic back-road projectile is in another league. It’s an epic experience and a fabulous achievement. M Power strikes back