Perhaps it\'s not the best time to review two convertibles as temperatures start creeping from mild to hellish, and the instrument display reads 40 degrees. A shade would be good respite, if only humidity levels weren\'t so high that today\'s weather should really be classified as precipitation. Yet I was thrown the keys to two soft-top cars, and after the tricky logistics of getting both of them home and safely parked away from hoodlums, I set about doing my duty. But I don\'t want to merely find out which of these two — the updated new Audi A5 Cabriolet or the Mercedes-Benz E 350 Cabriolet — is better. I want to find out which is sportier. Easiest task ever… The answer is neither. If you want an eloquent saga of tail-out hooliganism and the slicing and dicing of apexes, Jonathan Castle in the Mercedes-Benz SLK 55 AMG is on page 46. I\'m afraid I have you booked witha 9am appointment for a probing comparison. Right-o then, strip down and get comfortable on the throne, and we\'ll get this over with quickly. Speaking of stripping, the Audi A5 looks handsome, doesn\'t it? It\'s like a ripped jock just walking out of the gym shower. The Merc, on the other hand, is a bit confused, looking clumsy with the roof up, and insecure with it down, in that similarly awkward way when you\'re standing there naked in front of your doctor and you just know he\'s judging you, despite the Hippocratic Oath. I bet he Facebooks about it afterwards, too. The problem with the Mercedes is that it can\'t successfully shed the E-Class saloon\'s proportions, burdened with that incongruous rear fender character crease. When you drop the roof the rear end looks too heavy, like a huge, dragging butt of an insect. Or maybe this heat\'s just blurring my vision… (Anyway, Mercedes-Benz is rumoured to be working on the most thorough mid-life facelift in the history of the E-Class — the 2014 model will pretty much be a new car.) My vision\'s 20/20 when it comes to the Audi. The updated range has just arrived in the GCC, and the A5 Cabrio\'s new headlights resemble more a wedge, than the previous car\'s swoosh. It\'s dynamic and snarly looking. The profile is pure understated elegance, with a flowing character crease that should be at odds with the rest of the car\'s angular, Germanic straightforwardness, but actually works beautifully. This isa car that catches your eye, especially in showy red and on awesome 19in RS5-style wheels. The Merc rides on 18s that look a bit lonely in those wheel wells. Nothing much has changed inside theA5, but Audi is offering new materials and colours, optional sport seats or climate-controlled seats with active ventilation, and a choice of three seats for the rear, so that presumably you can torture an extra passenger by shoving them back there. Neither of these cars can accommodate real people at the back unless the driver is fine with wearing the steering wheel around his nose. Ingolstadt also swears blindly that the new A5 Cabriolet benefits from a highly rigid body, and refined vibrational comfort. However, I think the E 350\'s chassis is a lot more stiff than the A5\'s in comparison. There is plenty of scuttle shake in the A5 — OK, relatively speaking for these modern times — and vibration through the steering wheel, while the cabin is noticeably noisier than the Merc\'s. Drop the top at the push of a button, and wind buffeting also isn\'t on a par with what Mercedes is doing currently. To be fair, Mercedes-Benz is the current leader when it comes to lack of interior noise intrusion in all its soft-top models, so it\'s a tough task for the Audi.The saving grace for that wobbly chassis in the A5 is its all-wheel drive system, which balances out the dynamic shortcomings by offering grip that strips tarmac. Low-profile tyres on, like I said, 19in wheels do wonders here, but this is still no driver\'s car. The same goes for the Merc, which has the better-designed chassis and body but then decides to balance things out of favour by softening up the suspension and fitting comfortable rubber instead of something sticky. These cars are boulevard cruisers. And as impossible as it is to differentiate between them up to this point, it gets even more, well, even, when you talk about the engines. The Audi drops the old 3.2-litre V6 in favour of the company\'s brilliant new supercharged 3.0-litre V6 producing 272bhp here. That\'s downtuned compared to what this engine can do elsewhere,but torque is 400Nm from 2,150rpm andit gushes through the seven-speed automatic transmission like the engine\'s burning diesel. I love the velvety feel of the 3.5-litreV6 in the Mercedes, but maybe it\'s the nature of the softened Cabriolet here that makes this flexible, responsive, naturally aspirated engine feel a bit dull here. Justa bit, though — this is still one of the very best free-breathing engines on the market right now. It produces 306bhp like itdoes everywhere else, and helps theE 350 accelerate from zero to 100kp in6.4 seconds. Sounds all right, until you step on it in the traction-rich A5 and break the ton in 6.3 seconds. There\'s nothing in it really, but the first 30 feet in the A5 and it\'s clear who\'s quicker. Ultimately I still had to decide which engine I\'d rather have, and I\'m going with the Merc\'s 3.5-litre for its excellent fuel economy that trumped the A5 by about20 per cent over my test period. I\'m pretty sure it wasn\'t my lethargy behind the wheel due to the sun-stroke that convinces me of these cars\' unsporty credentials. As two drop-tops, they\'re sublime, smooth, refined, well engineered, and well designed for their purpose, with minor differences. The price and the subjective attraction to their design will decide it for you. I\'m going with the Audi, and I reach this verdict using alphabetical order.