I used the 4572 mounts because that's what Schoenfeld said I had to use when I picked them up (they are local to me). They said if I didn't use those adapter plates then they couldn't garauntee fitment. Basically if I didn't use those plates and I had a problem I was on my own. I don't even understand why Schoenfeld makes this header. They don't make headers for any other production vehicle, only race cars. But that is for a different thread.