as far as my review of the STOCK extra ive seen 2 of them fly indoors at a hobby shop i worked at. one by the rep from e-flite, and one by a local kid. they both wacked them a couple times hardly any damage. with all that carbon fiber theyre suprisingly durable(compared to others with no carbon fiber) and the flight was beautiful i didnt see any bad tendencies. they seemed to be doing 3ft diameter rolling harriers with ease and many other manuvers that would normally look more sloppy with a stock plane. thats pretty good for a stock plane id say, i cant wait to fly mine its weiging in at 6.5 with battery, with 2 picos no back cases, and 1 hs-55 for the ailerons, and a himax motor outrunner. 7.4 480 thunderpower