i believe(im not saying that im correct) that it is def possible to take a stock micro rs4 engine and put it in a xmod. both engines look exactlty the same size to me and i have both cars fully stock so i could see it in real life. i THINK all u have to do is just take the connection on the xmod mod motor rip it off and soler it onto the micro rs4 motor and then thats it. again this has not been tested by me im just saying and making a theory. hope it helps