Geez, a thread full of AJ's (or ex's) and a dodgy ex-copper No wonder the topic has turned to crap. 180: I don't disagree with you on those conclusions, and just for those who want the conversion the SS comes in at about 14W/m.degC compared to the carbon steel with a best of 36, so less than half of the conductivity. As well the stainless would be expected, as a polished product, to exhibit lower radiative properties, except that it becomes hot and glows into the light emitting spectrum, completely negating the polished finish. My view is, regardless, both products need to be coated or wrapped to retain thermal energy so neither is a better option.
To achieve the best result from stainless, for flow and heat retention purposes equivalent to the UAS manifolds, a significant fabrication expense would be incurred, which I guess is the fundamental issue, We can get the factory product and improve it, or spend a truck load of cash. The decision makes itself.