Sharing much of its architecture with the 12C Spider, the 650S Spider features a retractable hard top that's stowed above the engine and beneath the prominent buttresses behind the driver and passenger.
The transformation from hard top to convertible takes 17 seconds, while the sprint from 0-100km/h is significantly quicker at just 3.0 seconds. That's just as fast as the 650S coupe, despite the Spider's 40kg weight penalty.
McLaren says the 650's carbon fibre MonoCell chassis didn't need any extra strengthening to account for the loss of a fixed roof, and power from the 478kW 3.8 litre twin-turbo V8 is identical to that of the coupe.
0-200km/h performance is just 0.2 seconds slower at 8.6 seconds, while top speed is 4km/h less than the coupe at 329km/h.
Helping the 650S Spider rein in all this mumbo are a set of carbon-ceramic brakes and sticky Pirelli P-Zero Corsa tyres.
Sales are due to begin later this year with the UK retail price being the equivalent of $395,303 Aussie dollars at today's rates - roughly $37k more than the 650S coupe.