I chose the PT6A-20 for its safety of operation and its very high power to weight ratio – 3.2 times the standard IO-540 which produces 300 HP and weight 500+ LBS for a ratio of 0.60 V. PT6’s 550/287 = 1.9. Additionally, this Pratt & Whitney PT6 engine has the best safety record in aviation history with millions of hours of fault-free operation across commercial, military and general aviation globally. With a 5 blade propeller and a max 2200 versus 2700 RPM, N71RJ with the PT6 and MT propeller is also appreciably quieter than the IO-540 configuration. For more info please see; http://www.pwc.ca/en/engines/pt6a.