My DZ experience;

YS 160 DZ - 4 blade, short Hatori pipe, 30% Magnum Fuel, 7800 rpm
YS 170 DZ - 2 blade 18.1x10, short Hatori pipe, 30% Magnum Fuel, 8100 rpm

In 2007 tried couple 2 stroke engines, Webra 160, Mintor to make my models lighter. In the middle of season went back to YS. Very reliable. Noting can match it.