These things blow up mountains
no, he is not stronger or faster at all.
Lets see why...
his punches weren't even mountain level
Um.. yeah sure....Please continue I'll have your order ready in just a moment.
, Sensui blew away a mountain sized mesa with a shockwave.
What do you mean mountain sized? It was simply a Plateau
he doesn't really have any quantifiable speed feats either to be honest.
Sage Madara is triple digits (He's around Yusuke and friends speed if i'm not mistake his speed is higher but oh well)... He got blitzed by Gai.
he might be a more skilled fighter admittedly, he's had much more training, but he doesn't cntend in physical strength or speed
Here's your order sir.
So in conclusion Gai is above mountain level.
Only issue with this is that Gudou Dama nullifies ninjutsu and Sages are immune to non Senjutsu ninjutsu. Obito tanking the Biju dama objectively was not impressive. A base rasengan which was like tree/house level from Naruto slammed him to the ground when it was imbued with Senjutsu whereas multiple biju dama don't scratch him. It's selective durability.