Where do you live? I agree with the rest of them that it is your shocks. I have RD springs and custom valved BOGE on my car. If the shocks are getting a workout and it is hot in your area, then shocks (in general) tend to feel spongy. I would wait until the conditions cool off a bit to see if the ride is not as jarring as now. One other note, your shocks are too hard for the RD springs. Keep the RD springs, they are much better than the Bav Auto springs. Good luck, -brandjur