As far as servos, any of the high end Futaba, Hitec, or Airtronics servos would be my reccomendations. For steering .15 to .09 transit time (faster is better) with at least 180 oz-in of torque. For throttle .12 to .08 transit time (faster is better) with at least 150 oz-in of torque. I would also recommend digital coreless servos. These will probably run around $120 each, but servos are the one place you don't want to skimp!
As far as transmitters, I would recommend the Futaba 3PM FASST or Spektrum DX3S for the low end transmitters and a Futaba 3PK or Airtronics M11 x for high end transmitters. They all come with receivers so you won't have to worry about getting more until you get more vehicles.
As far as motors, I would recommend the Novarossi b21f for you first niro mill. It is a lower cost engine ($180) and won't have you cussing too bad trying to chase a tune
.