Ferrari California Twin Sound Exhaust System. The Ferrari California CAPRISTO Twin Sound Valved Exhaust System is a stunning good looking system with an astounding sound quality. This system bolts into the existing mounting points. No need for any modifications. The original vacuum lines plug into the CAPRISTO valve actuators, thereby the original functionality is retained. You will experience an increase in horsepower and sound due to a more efficient flow through the exhaust system (about 17 to 19hp). The first thing you'll notice is the craftsmanship and quality involved in the design of this exhaust. Crafted in true CAPRISTO fashion, this exhaust is using only the highest grade polished stainless steel (T309). It includes all mounting points and hangers.