Some have had that experience but no, they are technically efficient and usable beyond that point how well the complete system flows (both hot and cold side) and the type of waste gate actuators being used are major determining factors.
m a g l i t o SGP engine destroyed itself after 4k miles. New engine dropped in 11/05/2006. Details coming soon. sig photo by me effects by ZXRider(SoCal) The build up begins - progress - reassembly part one - part two