I was recently at a conference where I had the opportunity to meet a Russian engineer from TsAGI, their Institute for Hydrodynamic and Aerodynamic Research. We were at the Cosmosphere Museum near Wichita one evening for a banquet. He said that his first job out of university working for TsAGI was to perform wind tunnel testing on the F-22. He said, "Your F-22 can do some amazing things. Then we found a Soviet-era model of your F-117, so we tested it, too. We did not copy your F-22 while designing our T-50, we had a Lego-model that we did configuration development on and we converged on a similar design. The Chinese did the same thing when they developed the J-20 but they converged on a design that we believe is inferior."
It was very interesting to hear his version of the space race while looking over the space exhibits. There were photos of German scientists in the USSR and the caption referred to "Kidnapped German scientists". He took offense to this, stating, "You have to remember, this was just after World War 2 and the Germans killed 20 million Russians. This was not kidnapping, this was PAYBACK!"
Note that the Americans also had many, many German scientists after the war, too.