It would be interesting to find the cause of the stock exhaust manifold failing. Obviously it takes some years and exposure to road conditions to cause the failure to start. I've not heard of stock manifolds failing in the first few years of driving. Maybe over time the exhaust manifolds degrade/rust and then get splashed on with cold water when hot and "crack". Perhaps buy the Dorman replacements, and get them ceramic coated? Then install the new manifolds with the upgraded stainless steel fasteners with the lock tabs to maintain the torque. Sure it adds some cost but if it makes a reliable leak free exhaust for a lot less than headers it may be the choice.
I'd guess that exhaust manifolds have fallen victim to the whole "make them thinner, make them cheaper" mentality that has taken over all aspects of manufacturing over the years. of all the cars and trucks I've owned over the years I've never replaced manifolds due to failure. I was looking to upgrade performance wise. Maybe I've just been lucky in over 30 years of driving?
