Rear suspension

[fmicle]

I started hearing the clunking sounds ever since I installed the new springs (Progress, 1.4" drop) and shocks (Tokico blues). I shortened the bump stops by about half an inch in the back and about 1 inch in the front. Right after the install I took it for a ride and heard the clunks while going over the driveway curb. I thought the coils needed to set in. After that, nothing for more than a month. Then I had 2 adults in the car, one in the front, one in the back and heard the same sounds again a few times. I checked under the car and couldn't see anything bad, no rubbing, no scratching. I don't see how the sway bar could hit anything, since mine (Ultra Racing) is installed right under the axle...
I believe the clunking comes from the fact that my Progress coils are different than the stock ones, the first 3 spirals sit on top of each other so there is more contact between the coils thus, more potential for clunking noise...