Pink foam will work the same as blue foam... they're both extruded polystyrene foams. There's also grey and green out there and it's colored for product identification purposes. There are also different densities available... for a cowl, if I were making a one-off, I'd shape the foam, put a finish on it, fiberglass it, and chop/dissolve the original foam out... going that way it makes absolutely no difference which styrene foam you use.

BTW, I get my foam from a concrete company... they use it in various thicknesses for concrete forms and insulation.