The 1515 2.5D (1700kv) works pretty good on 5s for racing. I use the quark 125 with mine and it's been doing pretty good racing hear in the summer (no thermals).
woud that setup be able to beat a nitro powered 777 with a RB.c6 engine ?
my friend have that 777 and he still thinks that nitro's rule and i'd realy like to beat him on the track he he !