Default Edit Asia ext ROM and its Processes

I am a newbie and just got my XDA2 few days ago. This is a real good device although it's kinda expensive. I have read some tutorial on editing the locked extROM but it seem not for Asia version? I cant quite understand. I would like to delete some unnecessary stuff like Operator cab files. How do I do that to the 1.6 Asia ROM?

I heard that caller id process eat a lot of power. Is this true? What other stuff that is advisable to be closed/removed? Thanks