[Gustav]

You do have to dremel the input shaft very slightly to fit the bearing over,don't take too much off because it still has to key to the slipper plates.

For esc mounting,zip ties are your friend,i usually use servo tape underneath or strong velcro.
For the e-maxx it's common to make a right angle bracket that mounts to the unused side of the motor plate.some creativity is usually needed to find the best way to mount the esc,you want to keep the motor wires and battery wires as short as you can,and put the esc somewhere it's protected from flying debris and stuff.