you can use any JR FM 3-channel receiver with that transmitter. I've heard other brands may work but I not 100% sure which ones.

I use a Hitec HS-5625MG servo for my XXXNT. Works great and was only $50. It has 130oz.in torque and .14 sec transit time at 6V. Just watch your receiver pack voltage (all digital servos use more amps than a regular servo)