OK, so here's my theory. I'm getting the same clunking. At least it sounds similar. And it only starts after the car has been driven a bit. Stop and go traffic is the worst.
So I took off the left shock and checked the bolts holding the upper bracket (since I replaced the LSS shocks with Nitrons, I actually installed and torqued to bolts myself over two years ago). Bolts were tight, no sign of movement. Checked the ball joint nuts, upper and lower control arm nuts, sway bar links, all tight.
Took it for a drive and the clunking starts again. So, I'm thinking... what does it sound like and when is it happening?
Conclusion: the sway bar bushings have dried out (i.e. lost their lubricant), and the sway bar is "sticking"... whenever the suspension height changes, the bar should rotate, but since it's sticking, it doesn't move until enough torque is on the bar to "unstick" it from the bushing. When that happens, it makes a noise, and the force on the sway bar suddenly changes, sending a pulse through the steering to the steering wheel.
So, I sprayed a generous amount of all-purpose silicone lubricant into the bushings (you can reach them if you turn the wheel extreme left for the left wheel, etc.)
I vaguely remember this happening a few years ago, and I tried the same trick... seems to have kept the clunking at bay since then.
Note, there are lots of things that can go clunk... check your suspension regularly, especially if you track. But in my case, I'm pretty sure it was the sway bar bushings... that might explain the temperature sensitivity as well... the bar is steel, and expands more than the nylon bushings, making the fit tighter as friction or ambient temps cause the bar to heat.