now everything is almost clear they are using Multi threads [bat to detect threads number then ppx2 to speed up precomp or reflate] & the repack tools is srep , precomp , pzlip , mpz , reflate .... like what we use usually .. so a good compressed repack even using 4 or 5 methods + Multi threading = Speed + Good ratio
.. what i don't understand is how to encrypt the final arc file like they do