This has been useful for me to diagnose and fix my sport seat thigh bolster. It was making this annoying creaking sound every time I pressed the clutch pedal.
It turned out that the rivets holding the plastic frame to the metal base of the thigh piece were worn out.
The creaking can't be heard thru the picture but the rust can be noticed on the foam opposite to the rivets.
Once discovered it was a matter of drilling and punching the rivets out, then replacing with bolts, washers and nyloc nuts.
I could not have removed the part without reading thru this post. Thank you!