what's a good source of replacement half axles?
 

I need to replace the passenger half axle on our 95 impreza - the inner
u-joint is getting really bad. From what I've heard, the best way to do
this is just replace the whole axle. (correct me if I am wrong,
though).

There are a lot of sources for half axles, including on ebay. I don't
want to do this job more than once so what's a good source reliable
source of rebuilds? I take it most places require a core?

Thanks!
Remco