If an (ethnic) Jew were to become a Christian, a soul has come to Christ and salvation, and praise G-d for that, but...it is no more than if a Salvadoran or a Thai had come to Christ.
If an ethnic Jew returns to HIS OWN FAITH, he is doing that which a non-Jew cannot do, and is taking a position in the shock-troops of G-d in the end times.
That said, a person without the miraculous help of G-d, cannot "return" to that which he never had in the first place, so when I myself have met a couple of Jews that didn't know Bar Mitzvah from bar association or Mars bar, I felt I should just invite them to services and to join US.
My position would have been very different if they had been fleeing from that which they KNEW, in that case like the Prodigal Son, the answer would have been to reverse their steps, as Jesus said, and go back to their onetime status as observant Jews...
I wonder if Mr Micheal Savage is now a Christian of Jewish ancestry?