With tall sills, clambering into the cabin isn't the work of the moment, and once ensconced, the firm seats feel snug and a bit unforgiving. There's not much spare room in there, with a massive transmission tunnel, tiny door pockets, a ridiculously small glove box and shallow centre console. Fortunately, the 165-litre boot is large enough for a pair of squashy bags.
With a twin-dial instrument binnacle and twin rows of piano-key switches, this is a classic sports-car facia. There are big rotary switches down the centre console to operate the driveline options and Mercedes's rotary capstan control for the audio and sat-nav screen mounted high in the centre of the dash. It's all pretty much contiguous with the driver and sort-of comfortable, but with no space behind the seats, you have to be organised for long journeys.
There are 11 coachwork colours (Solar Beam yellow costs an extra £7,500!), three hood shades and 10 interior trim textures. Best, in our opinion is the satin gunmetal grey (Designo Selenite at £2,145), with a sail-cloth red hood and darkish leather with piano black highlights.
As you might expect, performance is suitably barnstorming. The standard Roadster will rancorously sprint from 0-62mph in four seconds with a top speed of 188mph, Combined fuel consumption of 29.4mpg and CO2 emissions of 224g/km. Equivalent figures for the C version are: 3.7seconds, 196mph, 24.7mpg and 259g/km.
Start up either version and the V8 throbs the air, bellowing defiance at the politically correct and dubiously ecological. Its width, crackling power and look-at-me appearance makes this a bombastic motor car; all latent power and portent. Out on the wide interstates of Arizona, the engine felt unburstably stentorian and unstoppably strong. With a speed limit of 65mph, it was all we could do to stay legal. And when the going got wet and snowy in the mountains to the North of the state, we found the traction control to be just as brutal. Experience tells us the handling is more benign than it at first seems, but with all that power, you need to take great care on anything other than race-track smooth and bone-dry surfaces...