Changing Gentoo's make.conf file
 

I was starting from stage one installing Gentoo and when I was configuring all the GCC options I left out I did not use -fomit-frame-pointer is this that great and if it is how can I go back and change it, and besides that should I add any more options. I've just started bootstrapping so I figure I might be able to change these setting before starting to install the main system.

Doesn't make a big difference, in fact when optimizing it possibly may not make any difference, see "man gcc":

"-O also turns on -fomit-frame-pointer on machines where doing so does not interfere with debugging."

If you want to emerge everything from scratch, have a look at

"emerge -epv world"

(-v shows USE flags), then

"emerge -e world".

Does that include -O3?