There's really no need to go back to stock. The extended OEM files you need are already built into the kitchen, so no need to "go back to stock to reload the extended ROM". Just clear your extended ROM and use it for storage. The CE ROM section (the part that the kitchen builds) gets completely rewritten during the load, so no point in "going back" unless your phone won't boot and nothing else has un-stuck it.
Of course, if you wan't some of the crap ware from the extended ROM, that's not built into the kitchen and you'll have to lower yourself to the stock ROM to get it again.
