Hey..
I tried using x3 config live to change my eeprom before changing my hard drive, but for some reason..it didnt change it (flash protection was on, hd was locked, i dunno) and it got me banned... so i wouldnt recommend it. Use ConfigMagic Final and compare eeprom serials before and after update to make sure that you actually changed your eeprom.
Some eeprom sellers, (zodiiak perhaps) finds a friend with xbox who isnt going to be using live, takes his/her unbanned eeprom and flashes it with an old one.
I would suggest doing account recovery to be on the safe side.