Good day!

I have 18" wheels on my car along with half shaft spacers. This weekend i finally lowered my car. Now i noticed when i get to 70-80+ mph and full throttle in any gear, i feel the rear end vibrating. I'm wondering if the wheels need the hub centric rings or what my problem might be. car only has 28k miles.

 

Sounds like the classic issue of CV cup pitting. Does it only happen on acceleration (not deceleration)?