The problem with the wrap, it exceeds the reliable heat range of the exhaust material, which leads to rapid oxidation ( view as rust) and metal fatigue, as the metal excessively expands and contracts thru every heat cycle. You can wrap SS and not have same downsides to a point, or wrap CI or Inconel, but mild steel will not last. My guess on the constant speed motors, they are not mild steel tube manifolds..

Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.