Hi Kevin. I have an Optima and wanna know how much will it cost to upgrade my old REV D and REV C boxes to the new one that use the 18650 batteries? I need the Oled upgrade on REV C too! Since I live in Brazil I'm planning send you my electronics at the beginning of April, and take it back on June 11, 2014, when I will be there on Cave Excursions. Is it possible to do the changes on time? Thanks.