I've heard that the crank is the same on every version of the CVH.

Rods should be the same on the non turbo. Flywheel is slightly smaller as the RST takes a bigger 220mm clutch. XR has the smaller one same as the S1 RST

Head is also the same. Various different versions of CVH head, but apart from the S1 getting sodium valves there was never anything beter specifically given to an RS model.