As stated before, steedspeed manifolds are no longer produced. So, look around the FS section for a used one. Stock manifolds are not weak. The constant heat cycling over a 10 year period does play a part in it. but the major reason for cracked manifolds is because of the stock motor mounts and the fact that the stock down pipe is braced to the engine...well the J pipe is anyway. So, as a result, there is no give in the exhaust system while driving. But the movement has to go somewhere. Solid mounts greatly reduce lash and a DP with flex section allows a good amount of movement which takes the stress off of the manifold. Get solid motor mounts and that should slow down if not stop cracks from developing. I had a crack forming on my manifold. It wasn't all the way through, but you could see it. I swapped in AWR 88's all around and that crack never got any worse and no new cracks formed. Then swapped the stock down pipe for a PEP down pipe with flex section and that would have helped as well. But by then, I had already swapped my stocker for a tubular MAM mani. But anyway, the cracks on manifolds are not all because of "manifold quality" or heat cycling. If that was the case, JDM Sam's manifold would have major cracks in it by now. But nope, his is in great shape and yes his is coated. But he also has solid mounts. So, as I said before, swap to solid mounts and if you can, find a PEP downpipe or get a custom one made with a flex section and they will help prevent cracks. Or if you can't do that, take the stock manifold out and get relief cuts on the flange between the runners
