No difference. AFAIK, they all use the same case, movement set-up and bezel click-spring mechanism. Yes you can swap a bezel from one into the other, and for those that use inserts (the 171 doesn't), you can swap them too. All other parts should be interchangeable as well.Other than band, dial face, chapter ring, hands, and bezel ring is there any difference in the case of the Seiko 200M divers that look like SKX007/009/011/171/A53/A55's?
How hard is it to swap the bezel ring (I assume I am using the right terminology).