(Maybe) Definitive speakers

Hello everyone, I would like some suggestions regarding important speakers, "maybe" definitive as the title says, with the following characteristics: - Ability to reconstruct stage, especially in depth, simply top. - Maximum transparency. - Excellent rendering capacity of microdetail and harmonics. - Excellent speed. - Good extension at the bottom, possibly excellent. - Excellent control and articulation at the bottom. - Zero listening effort, without giving up the realism of reproduction. In short, the characteristics of the best mini speakers combined with those of excellent speakers if not full range but at least more complete. Virtually the perfect speaker ...: $ The dimensions of the listening room, average reflective, are 600 x 450 cm with speakers positioned on the long side up to a distance of 70 -80 cm from the back wall. They will be driven by a PS Audio BHK 250 Signature. I would have a slight preference for American speakers, I'm in fact a strong supporter of geographic philology in systems building, but obviously I would be willing to have a good flexibility if it was worth it. Better if it were possible to listen to them in Italy rather than having to cross the ocean ... Budget up to 8000, even (above all ...) on used. Thank you Mario