The stock geometry should look something like this:
Those three grey lines going off to the left are the projection lines and although they meet well off the screen some 200" away, they are all pointing in the same direction to some degree.
If I zero the toe on this and sweep the suspension from 1/2" rebound to 1/2" compression there is .25° of toe change across the axle.
This is how the geometry looks lowered 1.5" (40mm).
Looks bad but the track rod projection line only moves below the instant centre by .36" over stock which isn't going to affect bump steer that much. The toe change for the same 1" sweep through rebound and compression is only .09°. Strange, but it appears to have improved if anything. I'm not going to pretend I understand that.
Here's how it looks if we then add a 3/4" extended balljoint which seems to be the most common size, add readjust the ride height back to the 1.5" lowered.
Oh dear, starting to look properly wonky now. The TRPL is now 3.1" below the IC. 1" travel gives 1.1° of toe change but in the opposite direction.
Finally, lets flip the track rod. I haven't done this before so this is new to me, I don't have any data on how much it is relocated by either so have simply moved the outboard joint 1" lower. By eyeballing it that has to be the minimum it moves.
That's now punted the TRPL off in the other direction, it's now 2.76"
above the IC.
1" travel gives 1.39° toe change, but back in the original direction.
Make of it what you will, it's by no means conclusive evidence but to me that tells me I shouldn't be bothering with either of those parts. There's nothing to fix, a lot to **** up.