I’m the only admin. I can invite you through an email I think. Send me a message with your email and I’ll get an invite out.
I get lots of requests to join but decline most because they’re spammers.
I would agree if you were replacing a certified part with another certified part ( i.e a MacCauley prop with a Hartzell prop) but in this case you are replacing one non-certified part with another non-certified part.