The teaser image above seems to indicate that the Regera – though likely to be based on the existing Agera and not an entirely new design – will feature restyled bodywork, at least around the front section. But it's the accompanying statement that tells us more.
According to the manufacturer, the Regera (from the Swedish for "to reign") will offer "a luxury Megacar alternative to Koenigsegg's traditional extreme lightweight race-like road cars" with a "never-seen-before combination of power, responsiveness and luxury." Considering that the last time the company used the term "Megacar" was on the One:1, we'd expect the Regera to pack the same 1,360 horsepower (one megawatt by metric measure, hence the term), if not more, but with added creature comforts.
That would leave the accompanying Agera RS to take the more extreme approach, likely to be stripped down and entirely focused on performance. Whether it will pack the same stratospheric output remains to be seen. It is clear is that while Koenigsegg has only produced some 115 supercars in the course of its history, it wants to offer the wealthy buyers of its next 115 an even wider array of choices – particularly as it expands into the North American market.