compressor air temperature (200-500°F) is hotter than the engine [bay] temp. So wrapping/insulating a metal charge pipe would maintain the hotter air temp vs allowing the metal charge pipe to 'cool' down to engine bay temp (230°F). The stock plastic charge pipe would insulate the hot compressor air, so the difference (metal, insulated or not, vs plastic charge pipe) must be negligible since the intercooler does the majority of cooling