For those who do not play "SD Gundam Capsule Fighter Online", the top level of performance customization that your Unit can achieve is Over Custom EX (aka OC 7).
[Although just recently, the South Korean server implemented a new upgrading system- amongst several other major changes to the game for Generation 6- which discards Custom/Over Custom in favor of a simpler Level 1-12 system. The Level System will eventually trickle down to all other international servers, including the North America server that I play on, but supposedly that will not happen for a few more years since it's so new in South Korea.]
Anyways, OC EX is the most notoriously difficult level to reach, and necessitates using the Unit in PvP battles a specified amount of times before you can attempt EX on it. (In the case of the video below, C-rank Units require a minimum 200 PvP battles.)
