The term Full Metal is bandied about in police, security, mercenary, and military circles, and roughly equates to the process of undergoing cybernetic upgrades and replacements so that there is more machine than man left. In its purest form, full metal equates to a person who has replaced their entire body with an android chassis, and their brain in encased deep inside the machine.
Loss of Gender Identity - a Full Metal cyborg no longer has their reproductive organs, and their apparent gender is residual. Their behavior will change slightly as they no longer have the input of sex hormones in their central nervous system. They may retain gender specific chassis, potentially even with exaggerated gender features, but these are as consequential as the fender flarings on a new car.
Loss of Traditional Gastro-Intenstinal Tract - going Full Metal requires a transition to a specialized diet of specifically engineered and processed foods that are absorbed by the vestigial biological systems remaining inside the cyborg. This can range from baby food like goods to a nutrient bath for just brains and eyes.
60% Machine by mass - the body of a Full Metal must be replaced with at least 60% machine components.
Loss of Biometric Identification - the most common biometric identifiers are fingerprints, dental records, and retina scans. A proper full metal cyborg has replaced their eyes and hands with machine components, and those that still have teeth are just disturbing, as they seldom actually need them.
The pros of going Full Metal are adopting the benefits of a machine body, including high durability, longevity, and the removal of biological weaknesses and urges. Likewise, the Full Metal has most of the strengths of the machine but cannot be hacked or short circuited like many robots are vulnerable to. Full Metal agents are able to use power armor weapons and gear without wearing a power armor suit.
The Full Metal cyborg has forsaken the majority of their humanity and suffer from psychological issues and traumas, and require regular maintenance and repair. Likewise, they still have organic components meaning that the Full Metal remains more vulnerable to extremes of heat, cold, and radiation compared to machines. Many actions and behaviors are ingrained reflexes, and a Full Metal can still have biological tells and reflexes, as well as psychosomatic tics and twitches.