I used the S5 racing frame for this build, its a bit of a mess but should be fine, any way it is an ok quad honestly the only issue I have is the race wire leds not fitting the 5 inch arms. but really solid frame nice job to the guy who makes these open sorce frames. oh and yes thats a 20x20 stack and yes I use two differnt motors on this quad but all for motors are 1600kv so we good!