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.
