I am interested in the new Zs. The "regular" z will come with a 23 Kaw and will go 11mph with blade speed of 18,700. The Super Z will come with 25 Kaw and will go 15 mph with blade speed of 18,350. Why the difference in blade speed? How is the extra ground speed achieved? When will the Kawasaki engines be available with a canister air filter system? What is the difference in price between the two units 60"?