If it had said 'stick' instead of 'put'....
Anyway, if theres enough space under the shell, then put the rx ontop of the center diff, then put the esc where the rx was. If theres a enough space that is- you will want ot be very mindful of all the little wires and leads concidering the spur and pinion are right underneath- use zipties and bases to route wires & bundle up excess.