Well, after more research I've come to the conclusion that it must be the rack. I realized I truly had no idea how the EPAS worked, as I always thought it was just a version of traditional hydraulic assist but with an electric pump. Yeah, oops. That explains why I could never find the pump assembly....
Anyway, I've been noticing more steering drift lately as well which seems to have gotten worse since trying to diagnose the mysterious "clunk" that I mentioned. The clunk I thought was a loose tie rod but I've since learned that it only happens when the steering wheel crosses center. If I turn a lot to one side or the other and then start to turn back it won't do it, but will always do it when it crosses center by about a quarter turn either direction.
Additionally the steering drift seems to be accompanied by a large amount of slack at center which is why I'm drifting all over the road. I can't help but feel like the two issues are related. I also believe this is what's causing the shakiness in the steering as it's allowing for too much movement in the toe position of the tires causing an imbalance/wobble.
A lot of this of course sounds like loose tie rods but after inspecting for any "play" in the front end by jacking up one side and checking for in/out movement, I can't detect any slop between the two front wheels, they seem to be married nice and tight.
So point being, all of this had led me to the only reasonable conclusion - it's time for a new EPAS unit. Now seeing as I
do not have $1000 bucks laying around lol, I do have a few hundred on my amazon card so I'm thinking about this:
https://www.amazon.com/dp/B07J9NFTPF/ref=cm_sw_em_r_mt_dp_U_XBvyDbHY2M9YY
Has anyone heard of this brand? They claim lifetime unlimited miles warranty, so that's assuring... Also does anyone have suggestions on the 17" vs 18" vs 19" wheels based racks? Since my car was base V6, my OEM unit should be the 17" non performance version but I have heard the 18" has a better feel, and I believe this particular unit is for the 18". Any thoughts on that?