Its good to wrap your turbo downpipes and ex.manifold with those heat wraps.
For those who have doubts, make sure the heat wraps are soak in water for an hour
to soften the wraps. Wrap it as tight as possible to prevent future twisting and rubbing against steel surfaces/pipes.
By doing this, your pipes or welding joints wont get brittle and create cracking.
Once its soaked, wrapped and securely fasten with driveshaft ties, heat the engine up and slowly let it dry.
You will see how good it looks compared to dry wrapping. Doing it the right way will really help to cool the engine bay.