The Eibachs will be stiffer than the stockers but not by much. I would check your install work and make sure the upper shock and strut mounts are still good. Also check the struts and shocks for leakage as they might not be working properly. Bilsteins have been known to leak.
The powerflex bushings will be stiffer than the stock ones too. You did overall stiffen the car quite a bit...