What makes New-Types different from "old-types"? In God Eater, Lenka and Alisa are both apparently "New-Type" God Eaters. Two questions about that:


What makes someone a New-Type? That is, is that how you're born, or can you be made into a New-Type by some sort of surgery/magic/etc.?
Why are New-Types so prized? What can they do that "old-types" can't?
The weapons utilised by the God Eaters, the God Arc(Jin-ki) are split into new types and old types. New types having the ability to transform between a gun and a sword and can convert the Aragami it eats into energy for more bullets. Old types are just Jin-ki that only has one form, a gun is a gun, a sword is a sword. 


New types are called new types cause they use a new type Jin-ki. They are the same as normal God Eaters biologically with no other modifications on them whatsoever. They are made into God Eaters by injecting Oracle cells into them, same as the old types. Its just that they utilise a newer weapon.
The God Eaters that can utilise new Jin-ki are prized as to use the weapon you have to be compatible with a Jin-ki to utilise it and those that are compatible with the new types are rare so they are highly prized due to their higher battle prowess with new type Jin-ki.