Having a car with two keys is not out of the ordinary. And the drill usually goes like this: you put one on your key ring and give the other to your OH/pop it in a drawer somewhere as a spare then forget where you put it.
The Ford Mustang Boss 302, however, encourages a slightly different approach. Its second key (technically an aftermarket accessory - now there's a neat way to side-step emissions regs if ever we saw one) is called the TracKey. It engages a software upgrade on the Boss 302's powertrain control module (PCM) that alters more than 200 engine management parameters, most notably an increase in low-end torque.
Other tweakery to the 302's brain includes an adjustment to the variable cam timing, the ignition mapping, the engine braking, the fuelling, while as many soft 'daily-use edges are removed.
"It's not for use on the street" says Jeff Seaman, a Mustang powertrain engineer. "For example, the deceleration is set up to preserve the brakes, and the throttle response is very aggressive. A skilled driver on a closed course will really appreciate the benefits."
Not for use on the street. Ha. Naturally (as any petrolhead would), we ignored Mr Seaman's advice when we had the bright orange Boss in for a few days recently and, after a brief dalliance with the 'boring' key, switched to the red TracKey. Immediately, the disappointingly dull idle was replaced with a much more endearingly truculent, lumpy affair, reminiscent of a hot rod, or a 1960s stock car. Promising.
On the move, the more aggressive set-up is instantly noticeable, with a sharper throttle response, and a distinctly greater sense of urgency from the newly enlivened engine. Yes, the TracKey makes the Boss a little less smooth around town, but it's hardly horrendous and it's much more appropriate to a beefy orange muscle car (okay, pony car, but let's not split hairs). It feels, in short, like a fast American car should: rough-edged, potent, and just a little bit agricultural.
Agricultural is not how you'd describe the 5.0-litre quad-cam V8 once you're given the chance to get it wound up, however. Because this is a gem of an engine. Its trick cams and high rev limit, just as with its 1970s namesake, endow it with a real 1970s bespoke performance feel - this is a car that relishes in high revs in a way that's quite at odds with what you'd expect of a powerful Detroit V8.
It also thrusts you forward with a delicious throaty gargle that makes you wish you had a stretch sticky black two-lane Arizona black-top shimmering in the heat haze on which to mash the throttle, rather than an autumnal British B-road.
How bumpy that B-road is might also make you yearn for the smoother surfaces our Stateside cousins enjoy, because that live rear axle, despite the larger rear anti-roll bar, lowered springs (11mm at the front, 1mm at the rear) and adjustable shock absorbers still limits the Mustang's flexibility on all but the smoothest of roads. Having said that, it's still a fabulously impressive handler, with lovely, incisive steering and bags of grip (when the suspension isn't too taxed by bumps).
This, and interior plastics that would make a decade-old Focus blush, are definitely low points of the Boss, but well-placed pedals, a beautiful gearchange and
engine still make the car something that ought to make any car enthusiast dribble just a little bit.
Once you've done all the importing bits, mind, you'll be spending around £42k, and that puts it up against some rather talented opposition: lightly used M3s, Porsche Caymans (but you'll have to forego carrying more than one passenger), or even - for £7k less - a brand new Chevrolet Camaro...
Ford Mustang Boss 302 tech spec
Price: £42,000 (est)
0-62mph: 5.0sec
Top speed: 156mph (est)
Kerbweight: 1647kg;
Engine: V8, 4951cc,
Power: 440bhp at 7500rpm
Torque: 380lbft
Gearbox: 6-spd manual