should i play this in Japanese or is there now difference in text speed

Japanese saves around 9 minutes with text speed. There are no gameplay differences between the 2 versions.

Are you sure? I can blast through the first battle with only 1 enemy out 4 attacking me in the Japanese's version but I always get attacked 3 - 5 times in the U.S. version. Seems like the battle system or the enemy stats are a little different.

100%. It has nothing to do with the version. Battle system and enemy stats are exactly the same. Enemy actions are based on an RNG counter that begins from power on.

Ah, you are right. I actually got a no attack run on the English version. Thanks for confirming!