  We report on the comprehensive numerical study of the fluctuation and
correlation properties of wave functions in three-dimensional mesoscopic
diffusive conductors. Several large sets of nanoscale samples with finite
metallic conductance, modeled by an Anderson model with different strengths of
diagonal box disorder, have been generated in order to investigate both small
and large deviations (as well as the connection between them) of the
distribution function of eigenstate amplitudes from the universal prediction of
random matrix theory. We find that small, weak localization-type, deviations
contain both diffusive contributions (determined by the bulk and boundary
conditions dependent terms) and ballistic ones which are generated by electron
dynamics below the length scale set by the mean free path ell. By relating the
extracted parameters of the functional form of nonperturbative deviations
(``far tails'') to the exactly calculated transport properties of mesoscopic
conductors, we compare our findings based on the full solution of the
Schrodinger equation to different approximative analytical treatments. We find
that statistics in the far tail can be explained by the exp-log-cube
asymptotics (convincingly refuting the log-normal alternative), but with
parameters whose dependence on ell is linear and, therefore, expected to be
dominated by ballistic effects. It is demonstrated that both small deviations
and far tails depend explicitly on the sample size--the remaining puzzle then
is the evolution of the far tail parameters with the size of the conductor
since short-scale physics is supposedly insensitive to the sample boundaries.
