We don't know much about Kid i know, but do you think Luffy is already the strongest supernova yet or do you feel Kid will be shown to be stronger? Basically hype or estimations are allowed in this thread
Luffy low-mid diff at best - I put Kidd on no higher than Chinjao's level.
If its any higher, then there was no point for the Straw hats to have waited two years, they may as well have just gone to the new world like the other supernovas and gotten stronger there.
Edit: Can't see Kidd becoming hax enough to ever challenge Luffy. Even if he gets on Magneto's level in terms of his magnetism, I still feel like metal is weak compared to the bodies of these superhumans like Luffy, Doflamingo, Sabo, Admirals, Garp, Yonkos etc.
I mean Pacifista's which are supposed to be made of super strong metal, get one shotted by Luffy, Sanji and Zoro. Seen as the same attack from Luffy didn't one shot Caeser, it means that Caeser has a higher durability than the strongest metal we've seen so far and Caesar is a shit bag.