There are certain parameters that distinguish the Porsche 911 from other sports cars, and most of them center around the engine – whether it’s the flat-six setup or the rear-mounted layout. That used to also include air cooling but that went the way of the dodo in the late 1980s.

That leaves the 993 generation as the last of the air-cooled 911s, cementing its place among enthusiasts as the last of the “luftgekuhlt” Elfens. But which was the best of them? Like many things, that may come down to a matter of taste, but whatever yours may be, RM Sotheby’s has you covered.

The Canadian auction house is heading to Monterey with no fewer than four 993s, each of them presenting its own compelling case as the ultimate of its breed.

There’s a red Turbo S, for example, that’s not only one of the rarest (with only 183 examples made), but also the most powerful. Its 450 horsepower trumped the 402-hp Turbo on which it was based, and which was the first 911 Turbo to feature all-wheel drive.

Purists might prefer the yellow Carrera RS Clubsport which was essentially the precursor to today’s GT3 RS, all stripped out, with rear-drive, a proper manual, roll cage, and a naturally aspirated 3.8-liter flat-six good for 300 hp.

Then there’s what might be described as the best of both worlds: the GT2, presented here in white. The first iteration of the breed, the 993 GT2 combined the stripped form of the Carrera RS but the forced induction of the Turbo, packing the same 450 hp as the Turbo S but without the all-wheel drive system – a “widowmaker,” as it came to be known, and a track machine of the highest caliber.

Of course if you’ll only be using it on a closed circuit, you might as well go for the full competition-spec Cup 3.8 RSR – atmospheric at 350 hp but with better response and track-tuned suspension, brakes, cockpit… the works. There were only 45 made, and this particular example is rarer still, all decked out in red (instead of the usual white).

They’re all heading for the auction block next month, with the Turbo S and RSR listed with no reserve price. So for your money, if air-cooled Porsches are your thing, which would you want to take home?

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