When i replaced the turbo from my '98 Series 2 R33, i took the compressor housing off and literally BENT the compressor fins.
They’re hard, durable fins that bend back into place…were not talking about a great deal of movement, but enough to realize it isn’t steel.
Then took it to Kyp at ATP for a gander, and he assured me it was nylon, and then HE bent the fin in front of me for sh|ts and giggles
Its not hear say internet forum myth
I know, from my own eyes, proven fact