yak -3 came after the 9 although the designs were started first,and it was faster as far as anything i have ever read! it was smaller and lighter, i do not remeber about the motor, but i do know i have read that it could have been the best fighter of the war, with the exeption of amount of rounds, as is with all yaks!
i have been wanting it for as long as i have been playing and there are many threads about it, just do a search!