OK, so up at it early this morning as I need to get these control arms done today. I need the car to be able to move around so I can put the other cars on the lift tomorrow and install snow wheels/tires.
Oddly in the videos I watched nobody mentioned that you need to remove the front belly pan as well as the rear diagonals to get access but, well, you do.
The front belly pan is a bunch of metal clips and two plastic 10mm nuts on the front, another two on the back. You'll note in the below picture that I'm missing the brake cooling duct on the right side. I literally just saw that this morning and I'm bummed! That's a GT2RS duct and they're insanely $$$. Argh! Oh well, I've got a brand new set of GT3 brake cooling ducts in my basement stash, guess I'll run them instead. They're a far more palatable $17 each.

Rear diagonals are one 16mm nut, one 15mm bolt and one 16mm bolt. They get in the way of the split arm.


Ok, just three bolts per control arm, easy right? Hahahahaha!!!! Well, getting the front arms out was fairly straight forward. Lining up the "tuning fork" arm on the Cervelli solid caster block? Not so much. That took awhile, plus I had to use a bottle jack underneath the ball joint to set the taper enough to tighten down the nut. Fun!
Then I realized that the GT3 uses different brackets to hold the litronic arm (headlight level sensor in English) and of course I don't have them. Argh!! Ok, well, the shop needs to play with shims during the alignment anyways, I'll order a set and just bring them with me.
Get the front done, first pic is old and nasty.

New to me hotness

Here you can see the marks I made on the rear eccentric bolts to make sure I got them pretty much lined up correctly.

On to the rear. These are even less fun than the fronts, which was hard to believe. First off I got the 18mm gear wrench stuck taking off the ball joint nut as loosening the nut jammed the wrench into the spindle. So I got to spend a bunch of time with an open ended wrench tightening the nut enough to free the gear wrench.
Then when I went to put the new arm back in I couldn't get the "tuning fork" on at all. That's when I discovered there's a very specific sequence of assembly. Because of course there is, since this is a German car and all. But I digress. Anyways, sorta seat the "tuning fork" first, then put the ball joint in it's home with the nut loose, now using a rubber mallet seat the other end of the arm. Line up the eccentric bolt, drive it home, use a rachet to line up your marks. Now struggle with the "tuning fork" bolt and the solid caster bushings. Eventually get it all.
Torque on all these is 59ft lbs for the ball joints, 118 ft lbs for the tuning fork and 89 ft lbs for the inner bolt. Done! Reassemble the front belly pan and rear diagonal arms. Put the tools away. I was going to pull the front axles, differential and prop shaft but I ran outta steam and time. I may do that later on this winter....

This job rated a solid 6-7 on the "suck-o-meter". I'm glad I'm done and I don't want to do it again.
EDIT: Make sure you've got the holes on the caster pucks in line with the tuning forks. So they should be on a diagonal, both pointing in towards the center line of the car, lining up with the tuning forks. Like this...


This will be a good starting point for setting caster. Also if you install the arms with a bunch of shims in them, expect to have to adjust the toe in the front, at least as much as the thickness of the shims you've added...