Pretty much I just wanna know how much time does JAP save over ENG.

JP saves about I believe 25 seconds on text, plus with the mousehole glitch exclusive to that version, another couple seconds. That's about it for noticeable timesaves.

Good to know. Thank you!

I've been informed during HDlax1's run at SGDQ 2017, one of the guys said that in the Japanese version, your vacuum is stronger in New Game +. I don't know if he meant that genuinely in Hidden Mansion mode, or that JPN New Game + is superior to ENG New Game +. (This is said about 49 seconds in the run)

I don't know... he could be right or maybe he fumbled his words, but I just want to confirm something for sure: Is the vacuum stronger in JPN NG+ or is the strength of the vacuum in NG+ the same in both ENG/JPN versions?

What is the mouse hole glitch?

To answer Retro's question, The vacuum is stronger in NG+ for both versions of the game. To answer Mugg's question, When catching a boo in Butler's Room and Hidden room, we can walk into the mouse hole and skip the text that normally appears when catching boos.