Since the Release of Carbon in October of 2006, Carbon has been locked and virtually unmoddable. Finally after tirelessly working with the code, Dawid, known as NFSU360, solved the equation, and has the ability under his thumb for new user created cars to be imported into the game.
The Tool release date has yet to be announced, as well, the performance modding is yet unchanged, so for now, any cars imported would still use the original settings from the one it had replaced.
Carbon Modding news will be known when more proper detailed information becomes available from the original source.
There are only three source shots of this current NFS success.
Source: Carbon Geometry Successfully Cracked