Hm... pretty much nothing is documented on tests on that site. There is a Rechlin paper which claims about 670km/h from flight tests but condition of the plane nor corrections nor conditions etc. are not documented. Generally Rechlin data during early war was not corrected for compressibility, as an example FW paper giving Rechlin Fw 190 A-5 values has a note that the given speed is not corrected for compressibility. Later Rechlin papers (as and example Fw 190D-9 data) contain practically allways the note if the speed is corrected for compressibility. Generally when the speed was marked as Vw, then it probably was not corrected for compressibility but if it was marked Vwck, it was corrected for compressibility. The error caused by compressibility depends on conditions but at about standard conditions and at FTH it would have been around 20km/h.
Anyway, a Bf 109 F-4 in clean condition was a pretty fast plane, specially if the tested plane was some sort of cleaned up (polished etc.) sample. Other story is if the 1,42ata/2700rpm and was really released for service use. One of the main improvements of the DB 605A over the DB 601E was improved head cooling but it (the 605) was still restricted to 1,30ata/2600rpm until 1944. Again, the site above fails to show direct documentation that the 1,42ata/2700rpm was allowed.
gripen
