Question about hd upgrade on a fat ps3

[kingdrako]

I have a fat ps3 40GB hd running kemeaw cfw 3.55.....I have been trying to read on hd upgrades but the more I read the more confuse Im getting......I wanna upgraded to 250GB I get the size of the hd and the thickness and rpm......where Im getting lost is: do I have to install CFW again? or is this kept on the ps3 ram? With the XMB backup utility will this back up also my psn games (all got from a decent site ), or do I have to install all of them all over again? How about the packages from games on the external Hd?
I know this is a lot of questions but I just wanna make sure what are the pros and cons.... Im in really need of bigger hd since my last add on to my external hd needed more space on the internal......
Off topic question.....last game installed on external hd battlefield 3 was also installed on internal.....I have noticed this with a lot of games is this normal?

Thanks before hand to all replies.

[No0bZiLLa]

ANY data that you saved to the ps3 (including .pkg files/DLC/GAMES/PSN games/ANY DATA) will need to be backed up.

[kingdrako]

Ty for the reply no0bzilla, will the back up program on XMB do all that?