2nd Gen TL Type-S (info/advice)
 

https://cimg9.ibsrv.net/gimg/acurazi...7cc1e6cb0.jpeg
Was getting rotors and brakes changed, was informed the rear passenger side needed a part, what exactly is this part?

assuming you are referring to the rear upper control arm? The part you have appears to be an aftermarket adjustable type, did they explain why?

When installing the rotor my buddy told me that it was stable but there was subtle movenment coming from said attached part that is in connection with the rotor. He claimed it to be a tie rod?

no tie rods int the rear; tie rods are the interface between the steering rack and the knuckle of the front suspension; responsible for steering angle.

is the picture you posted from your car? if so, we are talking about the rear; if not and you are using an image you found to give reference: that's a picture of the rear and will add confusion to what you are asking.

Are you referring to part 20 in the link below?

https://dz310nzuyimx0.cloudfront.net...3efa15af6e.gif


https://www.oemacuraparts.com/v-2002...rear-lower-arm

This is a picture from my car, and yes location is rear passenger. And yes #20 looks like it’s about it what would that be?

that's the rear upper control arm (rear UCA).

Thank you for your time, and knowledgeable much appreciated 🙏🏼