The Koenigsegg CCGT, it was a GT1 spec car based on the CCX. By the time it was finished being developed GT1 the ACO & FIA changed the GT1 rules. Carbon monocoques were no longer allowed and minimum production numbers went from a total of 20 cars over several years to 350 cars over several years.
It sounds fantastic.
It’s full specs & more info can be found here.