JB Weld fixes all. :)
But on a serious note, I honestly don't know of any places that will rebuild axles. I've never had a problem like that so I've never had to look into a place to fix it.
My only suggestion is practice... Practice makes perfect. I don't know what kind of suspension setup you're using or whether you have an LSD or not, but investing in those things will make the drift smoother and easier to feel.
You should still try and talk her into the series 5 if you feel like owning a high maintenance vehicle... :(
Though, I've never driven a car as fun as an RX7.