Not fair, true, but intriguing nonetheless as the smallest GT-badged Porsche goes against its big, bad and much more powerful sibling.

These two models have exactly what the demanding driver wants from a car on a race track to post a mind-blowing fast lap time and have a hell of a time in the process.

There’s no denying the 911’s might, but the smaller Cayman GT4 is the one who keeps the traditional manual gearbox in the recipe, attracting an awful lot of demand from Porsche’s clientele.

Despite the absence of a manual gearbox though, the 911 GT3 RS is one hellishly-fast track weapon, offering near-500hp, one of the best double-clutch gearboxes in the market and aero bits that would make many a race car hide in shame.

No one expects the Cayman GT4 to lap the Silverstone national circuit faster than the GT3 RS, but just for the sake of knowledge Auto Express brought the two together to let us find out just how much faster the latter is when compared to the sole manual Porsche Motorsport-developed production car on sale.

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