I got the OEM spoiler from the local Ford dealer. I can't remember the list price, but they had a special going and I got it for $150. I believe it is the only one that uses all four holes. There is also double sided tape included in the package. You have to get it painted.
i got mine from late model restoration, it is a ford racing piece (i.e. OEM) uses all four holes $199.95 plus shipping plus having it painted. fitment is well OEM, so no fitment issues. IMO OEM and a body shop you trust is the only way to go.