rusted inverse torx on ball joint

[alberniken]

Trying to diagnose the infamous 'brake shimmy' which has recently gotten much worse on my 01 3.0.

Managed to get tension strut out to check bushing (visually looks fine) Found ball joint was very floppy, couldn't find slop in the socket by hand, but the spindle flops around easier than I think it should.

Tried to extract the joint, got one bolt loose with plenty of patient cussing, but found the second bolt is going to be a problem. It is pretty corroded and I cannot get the torx tight in the hole. If I try to twist, it rides back out.

From research here and elsewhere, I gather I have to pull the knuckle/bearing carrier?

Unless someone has a magic screw extractor. Not in a rush so I can soak it in pen-oil for a couple of days, while I seek a solution.

Pic of rusted torx