A very common upgrade for a naturally aspirated GU diesel Patrol, is the fitment of the Manta exhaust kit. The 4.2L naturally aspirated (non-turbo) motor in the GU Patrol was available briefly upon the GU's introduction, before the turbo diesel 4.2L motor was rolled out. Although it was very reliable, it did not have a large amount of power and torque, therefore many owners look for ways to improve the performance and economy of their vehicle. An easy way to do this, is to fit a Manta 2.5" exhaust. This mandrel bent, high flow system replaces the entire standard exhaust system (a high flow extractor replaces the standard cast manifold) to give you better sound, and much more flow. This leads to increased performance, as the engine is able to operate much more efficiently. The exhaust is also available as an "extractors back" system, replacing the last two parts of the factory exhaust for those just chasing an improved engine sound.