Matthew, welcome. You give no details about how the surround question was "determined". At this point I'd consider such a decision to be highly questionable, since surround effects add so much to our enjoyment of both music and movies.
A receiver, of course, has an amp inside it, and is entirely satisfactory for powering Axioms unless the power demands are so unusually high that a separate amplifier with greater maximum output capacity is needed. Otherwise, in the vast majority of applications, there is no such need and there would be no difference in sound at all safe(to your hearing)listening levels.
