The new V8 package is quite a bit lighter, and we experienced real world fuel efficiency gains in the neighborhood of 15%. The motors are are smoother and have greater punch out of the hole to bring the boat on plane quickly. At idle you can hear just a faint bit of V8 burble, while not loud, they are not absolutely silent like the L6 was at idle. The biggest difference is with the Adaptive Speed Control, which is a new feature that holds RPM during maneuvers, without adjusting the throttle. For example during a hard turn, in the past you would apply throttle to maintain speed. These engines will hold speed without touching the handle. It really does need to be experienced to feel the difference.