has anyone changed one before? if so how hard is and how much am i looking to spend?

 

That thing is a piece of cake. You can do it in less than 30min With a ratchet and some extensions. Disconnect the battery so you don't ground out while working on it. Get the intake pipe out of the way and you should be able to look straight down at it from the top. Be careful not to over-tighten the replacement as you could crack its casing.