So, I’m pretty new on coilovers but I recently ordered “BC Racing Coilovers” (Extreme Low) I put them on without adjusting much On the spring. About a week ago I adjusted it about 2 inches in the back so I was riding on more spring than shock but the rear coils are still bouncy as hell. I turned my damping and adjustment to all the way soft for all 4 coilovers. Any idea on why it’s bouncing so much? Or what I need to do.

 

Sounds like you didn't do the preload adjustment correctly.

First you set preload.

Then you set ride height.

Lastly you make damping/compression/rebound adjustment.