Ebay's spoiler production QC has been a bit lacking since they started doing aero parts for Aston Martin and Formula 1. Their molds for the PP1 spoiler aren't quite up to snuff, so sometimes fitment isn't exactly perfect.
It would be so great if there was a place on the internet where people sold OEM parts they were no longer using. Where they could just post the product and sell it to whomever, a huge audience.
Yeah, I'd think finding an OEM PP1 spoiler would be your best bet.