If this is the Y pipe, the part from the dealer is several hundred already There is a Dorman part, but it doesn't always fit right, so I prefer the Ford part. And yes, it looks like an octopus.
Considering the guy has to drain the coolant, probably remove the inner fender skirt, replace, refill, and test, this is probably not unreasonable. I had a dealer do this when I was on a Disneyland vacation in Anaheim. They billed me $1200, and they messed up the installation and it failed a year later. They never responded to repeated e-mails, so I was left with having to replace it again at my cost.
After the mechanic replaces it, make sure the hoses are not touching the exhaust manifold. That's how mine failed, and one other member here had his fail for the same reason. If you are not sure what we are talking about, it's probably worth it to have some one independent inspect the installation afterwards with that in mind.