Just wanted to post the price I was quoted for this on my 91 Jetta's 1.6 TD exhaust manifold.
Jet hot wants $109 US to coat inside and out the exhaust manifold.
Extrude Hone wants $380 to hone the exhaust manifold and $425 to hone the intake. Was considering both until I got the quotes. Would be different if there was a huge increase in performance and I made a living off of racing but since it is just an economizer machine, I don't think the cost is worth it. I might do the Jet Hot just to keep the temps down and it does smooth out the inside of the manifold some.
I'll at least port and polish what I can myself.