How do you render a £24 500 Nissan 350Z coupé obsolete at a stroke? Chop the roof off - but before all you disgruntled coupé owners start getting all Theatre of Blood on my ass I should add straight away that the coupé is a fantastic car.
It revived the "Z" blood line with its recherché styling (complete with all the currently fashionable jewellery such as the chunky, vertical, aluminium door handles, trapezoid headlamps and Audi TT-ish interior) and boasts one of the finest engines around: Nissan's aluminium 3.5-litre V6.
It even has a carbon-fibre prop shaft which, according to my dentist who knows about this kind of thing, tells me is the height of prop-shaft cool.
The result is a charismatic, bullish sports car - old-school in form but cutting-edge in execution - that made the BMW Z4 and Audi TT look anaemic, and the Porsche Boxster clinical and humourless.
But for all this, the convertible version, launched in March, is a more desirable car in virtually every respect, for a mere £1 500 more.
I hesitate to say this about something with a Nissan badge for fear you'll think I've lost my mind, but if you're looking for a car with the superior swagger, boundless thrust and the composed chassis of a Ferrari, for a quarter of the price, you won't do better than a 350Z convertible.
Far from being the fey, Fulham Road dandy its appears to be, everything about the Z - from the satisfying, machined heft of its gear shift to the gutsy surge of its engine and uproarious exhaust note - has been designed with a rare purity of intent: to send a pure thrill coursing through its driver's veins. The usual compromises involved in chopping the roof off are few; the benefits are damn near irresistible.
Unlike the convertible version of the Audi TT, the soft-top Z does not have to sacrifice its rear seats to give space to a folding roof - it never had any rear seats to begin with.
Though the opening is narrow, the boot is deep and there is space for the obligatory golf bag and, anyway, there isn't all that much room in the back of the coupé because of the dirty great strengthening cross-brace that takes up most of its luggage space (which, interestingly, the convertible seems to manage without).
More importantly, with the roof down you can properly appreciate the engine sound: a distant basso rumble which rises to an electrifying, red-line yowl that has you taking detours through tunnels at every opportunity.
Flatten the accelerator and the Z's gutsy 3.5-litre V6 fills its Lance Armstrong lungs, and begins, lazily at first, then with a cumulative urgency, to reel in the horizon, furlongs at a time. It is licence-threateningly addictive.
The extra 100kg or so used to strengthen the convertible's chassis costs it some straight-line speed compared to the coupé (half a second off the 0-100km/h time), but the extra weight helps make it feel more confidently planted on the road.
The additional load gives the dampers something more to work against and, consequently, ruts and potholes that might cause other soft tops to judder and wobble are steamrollered to oblivion - well, almost.
If power corrupts, after a few kilometres in a 350Z convertible you'll be invading oil-rich dictatorships on the flimsiest of pretexts.