Where can I find reliable data on maximum turn rates for jet fighters?
Imformation on the F-22, particularly performance and mission systems data remains classified, as with the F-35 airplane.  To the best of my knowledge there isn't much technical data available to the public on those subjects.

Now flight manuals for older fighter aircraft are readily available to the general public.  PublicIntelligence.net is a great source for these documents, as they have them for the F-14, F-16, F/A-18E/F, AV-8B, A-10, just to name a few.

Janes/IHS is not a great source for this stuff; their entries are more on the level of intelligence briefs and encyclopedia entries and are not likely to contain the information you ar looking for.