Changing OS completely on galaxy note SC-05D and galaxy s2 SC-02C I live in Japan and I would like to get these 2 phones but both of them is sold here with Google Android 2.3.7 Japanese OS. 

I was wondering if it possible to change that into a regular English version? 
If so, how to do that in detail, please explain as I am new to this.
No need to change - language can be changed within the OS. My only tweak was installing a better English keyboard from the Play store, since the stock Samsung one isn't very good.