Soviet,
I agree about adding the Yak-3 with the VK105 engine. It would make a good addition. The Tu-2S would also be a nice addition.
As to the Ki-84's performance, well, it really depends on which data they use. The typical data that is used in sims gives the Ki-84 a deck speed of about 345mph and a top speed of 392mph at about 20,000ft.
However, there is a lot of debate about that being correct. I have seen many posts here that claim those numbers were obtained by a proto type Ki-84 that didn't have an engine as powerful as the main production models.
In US tests, with much higher octane fuel than the Japanese had, the Ki-84 was faster than the P-51 at all altitudes up to 20,000ft. It peaked at 422mph in US tests.
HTC modeled the N1K2 with the low octane Japanese fuel so I would expect the Ki-84 to be the same. It might slightly exceed 400mph at its best altitude, or it might hit the 392mph spot on.