I'm not an expert but my understanding is no you can't just use any rx. Spektrum has their DSM/DSM2 technology so the rx must be the same. Futaba's FASST is different and the Airtronics FHSS is diffferent from both as well others out there.
i'm not an expert about radios by no meens but from what i understand only the spektrum recivers and the losi dsm recivers will work...any should work as long as it's a DSM reciver
Any Spektrum DSM1 receiver is supposed to work with DX3S, DSM2 receivers, on the other hand, will not. DX3R will work with DSM2 receivers and is also backwards compatible with DSM1 receivers.
hey guys spektrum updated the dx3s so it will work with dsm2 now...any radios bought in the last lil bit are compatible with dsm2...you can also send your old dsm1 dx3s' in to have them updated