Crap I just went through this exact issue and was able to solve the problem. Lowered the car on springs and developed a popping sound when turning either moving on at a stand still. Sounded like a spring binding. Frustrated and knowing I needed rear shocks I did full coilovers the next year along upper mounts. Same issue.
Just did my clutch and when the car was on the ramp I asked the shop to have a look -
It was the shield just above the steering ends

. Just found it after two years.
I bet you this is your problem.. well hopefully.
-B