I would be a bit hesitant to wrap the header pipes with insulation. Usually that leads to a much shorter life for them. Unless the pipes are made of heavy wall stainless steel and/or designed to be wrapped...i.e...aviation applications....the durability may really suffer. Cracks at welds and pipe erosion is common when the pipes are run at a higher temperature than they were designed to be run at or the pipe material was designed for. Hard to say on the FJR without trying it but finding out later is going to mean the pipes are trashed if it doesn't work out.