I'm not so knowledgeable in the matter of aircraft performance, but interestingly the Soviet planes are missing, and I was trying to find comparison between Luftwaffe and Red Air Force aircraft.
In general I'm also trying to understand how performance influences aircraft designation as a type. For example in Wikipedia most one-seater 'fighters' are called just that, but Russian sources refer to greater numbers of types such as interceptors, fighter-bombers, light fighters. I understand that Wikipedia is not regarded an authoritative source, but I have had difficulty finding out the relevant information online. I am getting a book on the subject, but the information is not readily found online it seems.
It's best to stick to the reproduction and transscripts of the original tests on that site and make your own conclusions. Stay away from the comparison articles, they're very selective with the facts and sometimes even manipulated, the author is unfortunately incapable to disconnect from his pro-Allied stance and stay objective.
It's much better and more worthwhile to focus on the origianal tests themselves, though keep in mind that those are selections themselves, there's some eagerness to publicize the only 'bad' tests for Axis planes, even if the author surely knows of other tests which puts the specific plane into a different light..
Just stick to the originals, forget the propaganda articles, treat what you read there with a bit of reserve and you'll be able harvest the finer fruits of that site without poisoning yourself with the rotten ones.
Ok, I'll try to find original performance data for German and Soviet aircraft. Luckily I have just the right person in Germany to help, and I know several people in Russia who may be able to help with some luck.
There are some tests regarding Soviet planes from the German test centre Rechlin. These are short ones, but generally interesting. In time, I'll present those on my site.
The best book to look for Soviet fighter figures are Gordon/Khazanov's volumes dealing with fighters, bombers and attack aircraft. These are very detailed about development, and have reliable performance figures for prototypes and serial production aircraft.
PS : It's difficult to find a common ground for terms on WW2 'fighters'. German manuals for the Bf 109 for example call it a 'light fighter'. This though is probably meaning that it's a single engined interceptor, as opposed to the twin engined 'heavy fighters' like the ME 110.
During to course of war, terminology got totally messed up.. for example some German Ta 152 datasheets use the term 'Begleitejaeger' (escort fighter) for some TA variants towards the end of the war, a term unknown in 1939... as the bombers 'would always get through' - on their own.. or not.