ALMOST have solved my vibration issue - need a bit more help

[speedyspaghetti]

Hey everyone,

So I'm still on my journey to track down an annoying steering shake and kinda loose feeling in my steering/car. Nothing big happened to bring the issue on - no accidents or potholes, I just drove the car one day and it started and has not gone away since.

The vibration is most noticeable after 80 mph and the car does not feel stable as it should. Also, when taking higher speed corners (anything over 40) the car does not feel as "on rails" as it used to. It feels like it wants to oversteer / the steering does not feel as stiff as it should. I have noticed that my driver side mirror vibrates a lot - which would lead me to think that the issue is on that side. This mirror vibration got a lot better once I changed the rotors but it is still there. The car is 2002 S with 88k miles in 6 speed.

Here is what I have done so far:

Tie rods (in & out)
Drop links (front)
Struts & Strut mounts (front and rear)
Control arms (front and rear)
Front tracking arms
Rear trailing arms (or tracking arms? they are the ones that go diagonally from the front of the car to the control arm. I have not done the ones that go straight from the chassis near the strut to the control arm - could these be the culprit?)
Wheel bearings (front)
Tires (Continental ExtremeContact DW)
Sway bar bushings (front and rear)
New rotors (front and rear)
New pads (front and rear)
Multiple alignments
Multiple tire balances

All parts are OEM.

The most recent things I changed were the rotors and those actually really helped. Both had very significant lips on them, so I image there must have been some out of true-ness/round on them as well. These got the problem to about 90% resolved but I want to get it to 100% before I give up and sell the car. I've been sooo many shops and no one really seems to be able to pinpoint it. A lot have said wheel balancing, but I've had the wheels balanced many times on Hunter Road Force machines and every time they come out about 1/2 oz out of balance but it does not resolve the issue.

What else can it be? I've tried swapping rims with another member, but that did not change the issue. Could axles/CV joints be the culprit? I know the PO put aftermarket boots on the CV joints so I imagine something was done there but I have no documentation. The car felt incredible for about 9 months from when I bought it, but since then it has been a nightmare due to this issue.

Thanks for any help!