Okay, I've been summoned (I'd have find this out eventually tho).
It seems Luffy holds the AP advantage (if Mega Kong doubles his power then he would be above 20KT instead of 10 while Luffy's considerably above 35KT).
Kong can use the stat amp to augment his speed 3x and gain some advantage of it, but considering most of his arsenal relies on blunt force sans his fangs he'd deal virtually no damage to Luffy. Either it is a big punch or a big rock, Luffy can dodge it, tank it, or reflect it with GGN Fuusen (especially any boulders), reflecting it back at Kong with the same or even more force behind, which would be no good for the big ape.
Luffy's also much more skilled. Kong's intelligence feats are the average for most animals in OP world, where even dogs can understand the human language and are aware of their surroundings. Not to mention that Mega Kong loses all the level-headed attittude, which is a big problem against someone like Luffy, who capitalizes on that to overpower his opponents by doing cunning and quick movements. The size difference also helps him since he's agile enough to take advantage of it, especially considering he can just move around by stretching his arms like Spider-Man would do with his webs.
Why is Kong Class M, anyway? The feat linked to his profile leads to the 814 Tons feat which is Class K. Luffy scales
to this, which is 7.5x greater than Kong's strength, and he scales to this in his East Blue key, from the very beginning of the manga. Skypiea Luffy is much stronger than that. So he could easily ragdoll Kong or BFR him with a strong enough punch.
Voting for Luffy, the King of Monkeys.
on't do that no need add.
