
For some rather nice and unusual Japanese panels, search using the phrase "Japan panels Dwonload"--yep, ya gotta misspell 'Dwonload' because the fella's Japanese. . . Comes back as www2u.biglobe.ne.jp/~LD-REP/japan_panel_page-2.htm.
For sounds to all of these aircraft, you can use the A6M2 sound file as an alias--actually, they already are aliased in CFS2, and those files will work fine. There are no newer or better files for the Japanese small radials that I have seen. C47s sound just fine with two Japanese radials on the wings. . .