Other respondents are correct, the ball joint is a Saab part and should be easy enough to get. It is tricky to change though. If you have my experience, you will have to modify a spanner to get into the recess and stop the unit rotating, as you try to remove it.
You will need a ball splitter. Mine is very heavy duty, but despite extreme force, the taper would not release. As a last resort I carefully used a blowtorch to force the unit to expand, while the splitter was in place. Shortly after, there was a loud noise as the two parts finally separated. After which the repair was straightforward.