Diameter of a direct power of a finite group

We present two conjectures concerning the diameter of a direct power of a finite group. The first conjecture states that the diameter of G^n with respect to any generating set is at most n(|G|-rank(G)); and the second one states that there exists a generating set A, of minimum size, for G^n such that the diameter of G^n with respect to A is at most n(|G|-rank(G)). We will establish evidence for each of the above mentioned conjectures.
Comment: 11 pages, extensively revised, unchanged results except proposition 5.9, removed section 5.4