I saw Modern AFV D.G, superb photos there are!! That's inspiring me very much!!
I have not seen though I have heard vacumform kit. I heard some maker "Air Press" and "Schmitt" that sold in the 1980's. I heard that at that time, it was rare to see them because the AFV market in Japan had reduced.
There are various rumors about TK-X. In the rumors, there are some prototype vehicles, and the open to the public vehicle is a inexpensive vehicle in that. Opening to the public has been limited yet, though there are hints about technical feature in photos and videos, I heard. In Japanese forums, a lot of guesses are done that based on some fragmentary technological stuff.
JGFSDS seems to thought Type 90 has enough defense ability. It seems that they will deal by an internal improvement of composite armor. Gun is also the same as it. They will straighten out that problem by improving penetrater and powder. Adding, long barrel is not used easily for narrow place in mountain country.
....well, these are all the secondhand knowledge of rumors.