Just for reference, was told by the ex-Chief Pilot of TAG when we were testing updated 600s for Canadian DND that "if you had a good tech who could keep the cowlings in alignment", then the 600 was a genuine 2,500NM aircraft. He also said the main problem with the Lycomings was that you needed to anticipate more with them as they don't accept rough engine handling like to CF34s do. Beleive latest 604s & 605s have ranges of just over 4000NM.