The Red Bull aircraft pictured has had the turbosuperchargers removed, as have most of the surviving P-38s. This is to save weight and simplify maintenance, as well as the fact that today they are display aircraft and are low altitude only. So, the sound of these birds today is not the quieter sound of the exhaust exiting the turbos. It's louder, not like short stacks on P-51, but just as melodious.