Gday dsm members

Asking for your opinion in the amount of work that may be needed to repair a welded diff in a Lancer Evo 2 that I'm interested in buying..

Here is the advertisement for the car, I wish to replace the center diff and remove the plates from the front drive shafts?? and have the awd back and working as normal, your rough thoughts and any ideas in what path will be needed to take to change it back to normal any input would be appreciated.

Thanks

http://www.australialisted.com/ad/contact/17761405