Those natural rivals are the Aston Martin Vantage GT12 and Porsche 911 GT3 RS, the latter manufacturer having pressed the former to drop the GT3 name to which it claims exclusive domain. There's a great deal that separates them, of course: one's got a V12 up front, the other a flat-six way in the back. But what binds them together is a common approach of taking an existing model, stripping it down, and tightening everything up to make it more of a weapon than a grand tourer.
What that means in the Aston's case is a rather high price tag, much higher than that of the Porsche. But scarce demand and speculation on the open market have left British customers, at least, paying as much for the GT3 RS as for the limited-edition Aston. And that takes both into proper supercar territory. So to show what else that kind of money can get you, Monkey has brought along a McLaren. Not the similarly track-focused 675LT, but the standard 650S... Spider, no less, and with worn hard rubber.
So which one performs best on the road? Which clocks the fastest lap time on the track? And which gets Harris' vote? You'll have to watch the video for yourself to find out, but it's well worth the 25 minutes of your lunch break.