dont worry about a new hdd...while this will work, coupled w/ a new eeproim, it would be better to just get the serial out of an old xbox hdd and use some utility to force it upon your xbox.
because they are banning based on hdd serial, if you change just your hdd, they will check to see if it is a retail serial because your eeprom was previously banned
but, if you chnage your eeprom and your hdd, they will just look at your hdd serial and see if it is banned because your eeprom wasnt banned and your hdd wasnt banned.