You got what you need for the simplest method..
-Get Config Magic 1.6 and install it on atleast your chipped hdd..
-Upload softmod eeprom.bin to Config Magic 1.6's /data directory.
-Clone the eeprom from your softmodded box onto your chipped box.
(Make sure you save a backup of the original if needed)
-Pop in new hdd into chipped box.
-Boot an installer cd and prepare the hdd..
-FTP whatever files you need to softmod the new hdd, or an entire backup if you choose..
-Lock hdd and pop it into softmod box..
You should now be good to go, I mod many boxes using this method.. Takes around 5 minutes..