Is there something in the water up in Ängelholm, Sweden? Koenigsegg is cranking out updated versions of its improbably powerful hypercars at an astounding rate.

This is the latest, the Agera RSR, arriving hot on the carbon heels of the Agera XS and gold-plated Naraya.

There will only ever exist three Agera RSRs, all of which are destined for a trio of Japanese Koenigsegg aficionados.

Koenigsegg has confirmed the three cars are part of the 25-strong Agera RS run, and as such owe their prodigious speed to an 1,160bhp-rated twin-turbo 5.0-litre V8.

Wondering what makes the Agera RSR different? It’s in the exquisite aerodynamic details. Instead of a conventionally supported rear wing, the RSR borrows the top-mount system from the One:1, which increases the high-speed efficiency of the wing and generates superior downforce. As a bonus, it also looks thoroughly evil, like Hades’ snowboard has been stuck to the engine cover.

The Agera RSR buyers also fancied being able to remove the targa-top roof once in a while, so their cars have been built with shorter roof scoops. The V8’s appetite for great lungfuls of air has been maintained, but the scoop no longer prohibits detaching the roof for storage in the Agera’s nose compartment for what must be the world’s most aggressive blow-dry.

Company boss Christian von Koenigsegg introduced the latest evolution. He said this: “Japan has been an important market for Koenigsegg since the earliest days of the company. It brought us great pleasure to work with our Japanese clients to bring the Agera RSR to life. The cars they have designed add a new dimension to the already exclusive Agera RS series.”

All three RSRs have been extensively customised, negating the embarrassment of rocking up alongside an identical megacar on your local Tokyo expressway. You never know, you might even catch sight of into that chap commuting in his McLaren P1.

So, we’ve had the Koenigsegg Agera, the Agera R, the Agera S, the lighter Agera RS, and now this RSR. Not forgetting the Agera One:1 and One of 1, of course. It’s an alphabet soup of speed.

And Koenigsegg’s still had the time to develop the absurdly fast and innovative Regera, which TG exclusively drove last month. Phew. Here’s hoping the ‘Segg lot don’t go running out of numbers or letters any time soon…