@Verhalthur: not a texture swap.... I renamed bones, transfered all animations, imported the burrow geoset and copied/pasted every event object with note pad in mdl format....
@Warlord Ajer'laroir: I didn't understand....
·if you mean you can use this and the crypt fiend models: yes.. it doesn't 'overwrite' the fiend model
·if you mean you can change the crypt fiend model and use this one: yes.. you have to change normal and burrowed fiend models in object editor
·if you mean you can use the original cryt fiend burrow ability on a custom unit: no.. you should create a new ability to change normal and alternate units