Hi Richard, I have recently upgraded my Speed 400 powered models to Brushless. I have tried several different options from Axi 2208/20 and Castle creations 25A to the really cheap options such as Welgard. I will admit that there is a clear winner with regard to cost versus performance. Motor - Typhoon Micro 6/20 ESC - Tornado 20 Amp brushless Batt - Tornado Professional LiPo 1000mAh (or above) 11.1v 25C Prop - 6x4 for comparible performance 7x4 for super power! The whole setup inc prop adapter costs in the region of £65 and you won't be dissapointed with performance or duration. All of the above can be purchased from those very helpful people at www.Overlander.co.uk