The KCM boost should bring him above Naruto's speed, but feats show that he's not that much faster. They are pretty much in the same league.
kcm give naruto a speed boost yes, but he was no good in shunshin before that. Giving minato kcm would not boost his shunshin because he already have shunshin of high level.
Kcm minato have 1 feat, and it not even as good as some alive minato feat. So feat wise, he no different to his base form at all. Not from what was shown. If kcm made any difference to his speed, dont you think he would have notice and say something.