From Wikipedia:
"The 200 Series Shinkansen trains resembled the earlier 0 series trains in styling (some later units had the pointed 'shark nose' of the 100 series), but were lighter and more powerful, since these two lines are mountain routes and have steeper gradients."

As Tha_Phantom correctly pointed out, Shouki and Yukikaze form different parts of Raiden's body. Also, their individual robot modes look quite different, so even if they were non-combining, they would still end up being different toys. At least by MP standards; just as MP Sideswipe and Sunstreaker are entirely different moulds. I was gonna say that you might get away with shared parts/engineering at CHUG level (e.g. Universe Sideswipe/Sunstreaker), but Univ. Sideswipe and Sunstreaker don't combine. At most you could do it if they were all limbs, but not when one is a torso component and the other is a limb.

Glad to see that progress on the MP Trainbots remain on track.