u cant use a spektrum module on a 4pk.I know that its not one that you listed but i love my ko propo euros. it has more functions than the dx3 and just as much as the 4pk but cheaper. also i've heard that the futaba receivers often times overheat for some weird reason. some drivers have to cut holes in the receiver box to prevent the overheat issues. best option go with 4pk with spektrum module and receiver.