New trailing arms didn't fix rear clunk

[986lp]

I have a new to me '99 Boxster. 85k miles. The car is clunking in the rear at low speed over bumps. Reading old forum posts, it looked to be a classic symptom of worn trailing arms. I've now installed new ones (TRWs), but I'm still hearing the clunk. It may be a tiny bit better than it was before.

What should I check out next? To my knowledge, all the suspension is original.

Thanks for your help!

P.S. I don't know if this is related to problem, but the left arm was a lot more difficult to install than the right. My procedure was to screw the front bolt to the chassis and do the coffin arm bolt last. On the left side, the trailing arm did not line up well with the control arm—it was about 1/8 to 1/4 inch too short and required a bit of force to push the control arm and trailing arm toward each other to get bolt through the hole. The right side needed some nudging, but very little and was pretty easy to do. I don't know if this means anything.