Complex sentence: The Flat-plane crankshaft is a design that is no longer used in most mass production road cars as it carries more vibrations and is inherently much louder than a Crossplane crankshaft; however its higher rev limit means it remains useful in sports and racing cars.
Split into simpler sentences: The flat-plane crankshaft is a design that is no longer used in most mass production road cars as it carries more vibrations and is inherently much louder than a crossplane crankshaft. However, its inherent higher rev limit means it remains useful in sports and racing cars.