Here’s a TDI bit of info that is probably useless to you.
The e9x coupe and convertible (e92 and e93 respectively) have plastic front fenders, like a Saturn or a first gen CRX. The e90 M3 would also have them as it has the coupe front end. They can and will crack. I first noticed this on a local e93 with a chunk of its drivers side fender missing and I though “that can’t happen with a metal fender, that looks like what happens to Saturn’s “dent resistant” panels”
My theory was confirmed by a Hoonigan Bonus video where one of the staff’s e93 had a cracked fender do it being lowered and the tire rubbing on the fender.