Just found this on RCG, DJI is now including the E300 tuned propulsion system at no additional charge on f450 and f550 ARF kits. Anything ordered from DJI (by the distributor) after Feb 24th will receive the upgraded system. I've heard great things from those who have upgraded to these of the f550. Very tight and responsive, balanced motors and props, perfect upgrade for FPV or AP/AV rigs. So now the DJI F550 photography ARF comes with: F550 H3-2D Naza v2 with GPS E300 propulsion system All for 799 US. Heck of a value there. Here is the Doc on RCG to retailers: http://www.rcgroups.com/forums/showatt. ... 1393044226 May have to sign in to view the link.