nullThe picture is from the reference book, page 384: The secret horsepower race -> Calume Douglas. These spesifications are difficult to read so I have taken the liberty to interpret the picture from the book with the Fw 190 D9's speed at sea level from your game - 560 kph, and claims of topspeed i higher altitude of 680-690 kph from many internet pages- se the drawing.
I know that this may not be proof, but it indicates strongly that Fw 190 D9 have rom for more development.
So to whom it may consern: Please, please update the Fw 190 D9 so it can take its place as one of the best fighters of the war and the best fighter on the german side. We vil all profit from that.
Yours arey51