Car sagging on driver rear?

[Dirtsquirt]

The drivers rear of my car is sitting a good 3/4-1" lower than the passenger side on my M3. Both fronts are approx the same.

Rear bushings looked shot so I just swapped subframes for one with known good bushings, which didn't help. Current setup is TMS J-Stock w/SusTech sways.

Is it possible that the spring collapsed? I can't get under the car when the suspension is loaded to take measurements but when it was on the lift everything was a-ok.

-Dan

[whodwho]

Swap the rear springs from side to side and see if changes.