For the purposes of kinetic heating, which is what you're discussing in terms of providing a restriction on upper speeds, the colour of the body isn't going to matter.
The colour of an object will affect its temperature as a result of radiative heating i.e. a black car parked in desert heat will get hotter faster than a white car in the same conditions, because the black absorbs more of the solar radiation, while white reflects better.
But the effect of a jet of hot (or cold) air on both bodies will be essentially identical. Once the boidy is hot it will radiate itself slightly differently, but for the kinds of temperatures you're discussing I don't think it matters.