persoanlly if you can afford it, I would say get a good radio and a spektrum set up, I hate the DX radios, I find they arn't very linear, and its harder to drive smooth with them, IMO youd be better off getting a used Airtornics M8, or Futaba 3PK, then you know you wont ever have to get another radio, and then get a kit so you understand how it all goes togehter, and you can also do any mods or upgrades people recomend right from the start,
now if your on a budget and have to get a RTR, then the DX radio is better because most RTR cars come with total garbage radios, another good RTR is the CEN matrix, it comes with a nice digital radio, and decent servos to start with,