It seems to me that the sections of pipe under the wrap will get hotter than the rest of the exhaust. Whether that's an issue or not is unclear. But that was a concern to me.
That's why I went with the shield: It doesn't trap the heat, it only blocks the heat and limits the rubber components and differential from getting too hot.
2009 E90 M3 | SG | FR | 6Speed | Akrapovic Evo | JRZ RS1 | StopTech Trophy | Cantrell Brake Ducts