there is a size conflict between the XT6 axle and the EJ knuckle inner seal.
I am not sure if the ~.078" larger diameter of the XT6 axle will cause premature wear or cause fitment issues, but it is something to keep in mind.
if you haven't already sourced the axles, you could go with a 93-94 Impreza Fwd manual trans. axle, 23 spline DOJ and proper outer that will fit perfectly with your knuckles.
Ben