turbo bags are by far the best, they keep the heat sealed in the exhaust housing, even after a hard flogging i could work around my engine bay... going more for show with chrome i changed to a heat shield, although it doesnt quite heat "as" good, if made properly it still works great... the difference is and magazines have agreed, is that the turbo bag can directly touch components and can sit directly on the turbo itself, where as the heat shield must sit around 2-3cm off the exhaust housing itself so heat doesnt trvel through the metal...
in my situation it is a high mount, not low mount, but in either appication id recommend heat wrap and some form of heat shielding wether it be bag or metal plate
but the bag is the better item.
ben...