I won't do the manifolds myself, I'll let my wife's shop handle it. I tried replacing them years ago on my first generation and gave up. Is there an engine that's harder to replace manifolds or plugs than the 5.4?I did my passanger side last summer and it was a slow process but I got it done. I wouldn't wait too long though if I were you. As they get older they become way more difficult. Ford also offers stainless studs and nuts so you'll never have to do them again