Jet Hot sterling silver
It seems obvious that Jet hot had not been mentioned? They charge me 250 for small block pipes and 300 for big block pipes, both prices include return postage. I get the sterling silver coating done inside and out and have never had the coating dis color with any of my customers pipes or any of the many I have used myself. Other places do not coat the inside of the pipe and this is where rust will come through your bends first. They tell you that they can but they just spray into the pipes and only coat the inside partially at best. Jet Hot uses a medium that has the coating material on it and they extrude it through each pipe to paint the inside completely. This is how it was explained to me by jet hot some years ago.
The cost difference between places is real minor to what the nice set of pipes cost you that you are trying to protect.
They have a web site and they do not give me a kick back so look at them and decide where your money is better spent
Bruce