From a quick look at the specs it seems to be "a" replacement for the 550 Series - which is now the 560 and 590, both seem to be available in 2 or 4 Seat Configurations. The 560 basically looks unchanged continuing with the Briggs engine (16hp twin cylinder, air cooled, carbureted with a top speed of 28mph) while the 590 has a slightly larger fuel injected and liquid cooled twin cylinder engine rated at 32hp with a top speed of 45mph. I am assuming this is a Kawasaki engine but that is just an assumption...