Like i know the Japanese version is faster but exactly how much faster? and what is the possible max speed for both versions?

I don't believe that it has ever been calculated, but I do know that it saves maybe 5-10 seconds on the Gordor dialogue before Raikou alone, and that carries over the whole game because of significantly faster text. I don't think anybody has ever taken the game seriously on a language that's not Japanese so there's no good estimate.

Well i guess there is really only one way to find out and that is for someone to actually try and get the fastest time on the English version. At least then we would know how fast the Japanese version could possibly be as it is faster than the English version and that is just stating the obvious at this point XD