I get that a phone with a bad ESN/IMEI cannot be activated. My question is, what part(s) is(are) associated with the ESN? Or in other words, if I bought a 5 with a bad ESN for parts, which parts could I use (or rather, which parts could I specifically NOT use)? This is kinda like the eternal question "Where does the soul lie?", accept less ethereal and more literal with a definitive answer... "Where does the ESN lie?" My current 5 is on the fritz and I need to replace a few parts, but don't want to pay a dealer or Apple full price for each one. I'd rather buy one off CL/Ebay (with a bad ESN) and just frankenstein the parts into my phone to regain full functionality. If you care to share your thoughts on that subject, you can read and respond to this thread.