x64e is rarely used for vehicle files any more, most of the day one vehicles have since been updated in a patchday dlcpack, in the Comets case, Patchday13ng. The game is pulling the files from there and not x64e, which is why you're not seeing your new model. Put the yft and ytd files in the equivalent patchday folder to make it work.
ah ! interesting ! I test it now
Ok perfect, thank you very much I learn something