Dorman is a major supplier of new (not "recycled" or otherwise used) repair parts for all makes of cars. www.dormanproducts.com . All of the new aftermarket exhaust manifolds are cast in China. Some of them are better quality than others -- you know how it goes, they might all come from one foundry, but the good ones go to the high bidder, the decent ones go to the next-highest bidder, the passable ones go to the third-highest bidder, and the rejects go to everyone else...then they all get sold on the American market where buyers get not more than what they pay for. The Dorman items tend to be the good ones.

I don't think powder coating is going to be compatible with the high temperatures an exhaust manifold operates at, but the person to get with is Leanne at Phoenix Specialty Coatings. She makes powder coating walk, talk, and do backflips; she is my go-to for any and all questions and work. If there's no high-temp powder coat that'll work, she'll probably know where to send you for a different kind of surface finish.

Whether or not to have the manifolds surfaced together depends on the condition of your intake. Not a bad idea to do it as long as the shop that does it for you doesn't brutalize them (take off too much material).

It is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.

It is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.

Jet hot/ ceramic coatings will certainly stand up to the heat of the manifold... The only thing to consider is that the coating will actually help contain the temp inside the manifold,all good for tube headers,but,on a cast iron component the increase in material temp will cause it to expand more...a lot more, I have experienced this on a Hemi 6, to the point you could see the witness marks on the gasket and washers,it was a marked increase in movement over the non coated manifold. This may or may not be an issue,but over time my concern is the manifold may eventually crack. The modern exhaust manifold paints seem to do a great job and that's what I ended up using on my Nos slant manifold.

I thought these might not be so good for me since all my surfaces have or will be machines flat

As far as prep goes I had it sand blasted so it was very clean inside and out prior to ceramic coating. I've done a few manifolds with cast iron coloured manifold paint,if the part is a used item and you bead or sand blast the surface prior to painting it lasts very well and a lot cheaper than ceramic! I did my daily drive when I freshened the engine about 35000 miles ago now and it still looks good.... But for really nice builds the ceramic is the winner if used on the right components,it's just expensive.