Ugh, I got all my 1984 collectibles out and totally forgot to include the Super X! This is the Toho Machine Chronicles model. It's about 2.5 inches long and has tons of moving parts. The main headlight opens and closes, the big missle launcher on the roof raises and lowers. The smaller weapons bays on either side can be displayed opened or closed, and the three large gun turrets underneath can raise and lower and swivel.
According to the internet the official size of the Super X is 27.2 meters long, which puts this model at about 1:428 scale. That's within a millimeter or two of the 1:400 scale (roughly 8 inch) Kaiyodo model kit. So they're basically perfectly scaled with each other, which is pretty awesome!
That also means it's in scale with the cybot-based Marmit Monster Heaven figure, which is almost the same height as the Kaiyodo model.
Sadly, it's much too small for the X-plus 30cm figure, but they still look cool together.