Just got mine back today. Got the part the next day and install took only a couple hours. As for how it feels, it could be placebo, but it feels smoother and better. I don't know if it is steel or CF. Maybe it feels a tiny bit less powerful but the power delivery in conjunction with the transmission is smoother. Had a loaner 330i m sport brand new and I was so happy to get back in my 2017 m4. Too many buttons inside and the driving assistance nannies were intrusive. Also the suspension on the freeway couldn't compare.
You should look forward to the recall and report back on your experiences after!
