Vauxhall VXR8 GTS

Does the brutish appeal of the Vauxhall VXR8 extend beyond its in-your-face looks and garish paint? It’s certainly far less subtle than the Mercedes: the contrasting black nose, hi-vis LED daytime running lights and sheer size all ensure it has real presence.

Inside, it follows a similar approach, as an aftermarket-style pod of motorsport-inspired dials on the dash leaves you in no doubt about the car’s high-performance aspirations. But if you look beyond the racy add-ons, the cabin struggles to live up to its price tag.

Compared with the Merc, there is a huge variety of materials on show. The textured plastic over the instrument binnacle and glovebox is smart enough, but harder plastics lower down – and the shiny material on the centre console – give the dash a low-rent and busy look.

Ebony trim behind the air-con switches and carbon-effect plastic around the gearlever only add to the confused appearance. The finishing touch is the metal GTS strip beneath the stereo, which has sharp edges. It all falls way short of what you would expect in this price range.

The soft chairs lack side support and the unusually large steering wheel feels cumbersome and cheap. But on the plus side, big seats and a decent driving position mean it’s easy to get comfortable, plus there’s bags of room in the back and the boot is spacious.

There’s less room to play with under the bonnet, though. The huge 6.2-litre American-sourced engine is all-aluminium, and closely related to the unit you’d find in a Chevrolet Corvette. The VXR8 lacks the instant response of the AMG motor and only really gets going once the revs have risen beyond 3,500rpm, so you don’t get the sense of effortless acceleration that characterises the incredible Mercedes.

Our test car was fitted with a traditional six-speed auto, but judging by this experience the cheaper manual transmission would be a better bet. The self-shifter kicks down too readily and its changes are laboured, even if driven in manual mode. The box isn’t the only problem, as the exhaust resonates at 2,000rpm, booming through the cabin noisily at a constant 70mph cruise.

Speeding up or slowing down lets you escape the drone, but that is hardly the ideal solution. And despite its raucous motorway soundtrack, the VXR8 doesn’t pack the aural punch of the Mercedes when it matters.

The car’s handling does little to improve matters. Even though the adjustable dampers provide Performance and Track Mode settings, the ride comfort leaves plenty to be desired. The GTS isn’t as stiffly set up as the C63 AMG, yet its suspension struggles to cope with coarse surfaces, so on anything other than smooth tarmac it is fidgety and unsettled.

These dynamic shortcomings continue in corners, where the Vauxhall struggles to match the authority of the Mercedes. It turns into bends well enough for a car of its size, but there’s little urgency to its responses and the steering has neither the confidence-inspiring weight nor the feedback you need from a true performance car.

Push on, and the Aussie brute’s softer suspension allows too much body roll, while the brakes fail to match the AMG’s. A generously equipped and spacious cabin are the VXR8’s biggest selling points, but the lack of handling finesse, flawed performance and poor interior quality are thrown into sharp focus by its opponent.