Chosen Solution
If I switch a 7th gen 160Gb classic ipod from the original thin rear case to a thick rear case (to accomodate high capacity battery) do I need to switch the headphone jack from the thin to the thick model please?
Yes but the part is fairly inexpensive. Demigods.com has every part you need including motherboards. They also have iflash setup to replace the hard drive. I purchased the 2 slot iflash with the chrome back with 256gb etched on the back.
