HTTP_*_VARS and REGISTER_GLOBALS

Hi, Just a few questions. I turned REGISTER_GLOBALS on in php.ini, so all EGPCS vars can be accessed globally. Are there any advantage of turning it off? If yes, I am trying to use HTTP_*_VARS with REGISTER_GLOBALS off so that the scripts are more clear and organized. The problem is that I already have a lot of scripts written under the "REGISTER_GLOBALS on" mode. Is there a easier way to change the scripts instead of modifying every global vars to $HTTO_*_VARS[*] in each script under the "REGISTER_GLOBALS off" mode? Thanks a lot. - Bernie