How big are the brushless motors for a 1/10 scale touring car? is it small or about the size of a normal motor? and do i have to break in a brushless motor?

they are 540 size - standard size for 1/10th.
as I understand it they dont need breaking in as there arent brushes to bed onto the com like a brushed motor.

is a 540 small? or the size of a brushed motor?

brushless cans are the same exact size as any stock 1/10 motor. Thats 540 size. Bigger trucks, like the e-maxx, run 550 motors. But brushless is 540, therefore it should fit in any 1/10.