I bet the construction is the same as the current Crosstrek which has the same basic setup with different styling. Looking at pictures online, it doesn't seem like there's any functional difference in the Crosstrek fender, just an added on plastic cladding. As I said, it might make minor trimming easier as it doesn't have to look even remotely pretty. But if you want to go bigger, you'd end up cutting off the mounting holes pretty quickly.
