You've got a Boxter?!?!.....
Here's a link you might try:
http://www.fwdaxles.com/fwd_products.html
Seems like they have a complete selection. Here's another:
http://www.driveshaft-axle.com/
...and another:
http://www.cvunlimited.com/Products.htm
I checked online with subaruparts.com, they offer new axles at $328.89 ea. Usually re-man's are about $100. ea. I never could get through on their 800 no. so I can't confirm whether they've got rebuilt ones available.
-Mark