Since both versions of MI:3 use the VC1 codec, the video content itself is identical.
PS3 doesn't do any color correction to the image. If anything it's output is the closest representation of the digital data.
Any "advantages" in color he sees HD-DVD player connected over component has to be just signal degradation. Unless the HD-DVD player is artificially adjusting contrast or saturation. And that is the sort of thing a player should not do.
If he played it on a HD-DVD player with an HDMI 1.3 connection it should look identical to the PS3 output color wise.