Complex sentence: It found its most famous application in the North American P-51 Mustang fighter, where it vastly improved that aircraft's performance at altitude, transforming the Mustang into an outstanding fighter with the range and performance to escort heavy bombers over the continent.
Split into simpler sentences: It found its most famous application in the North American P-51 Mustang fighter, where it vastly improved that aircraft's performance at altitude. This fitting transformed the Mustang into an outstanding fighter with the range and performance to escort heavy bombers over the continent.