This is what I got:
Chasis -- Mine had two layers but it seems they don't sell that anymore. This is quite close to what I have and the motors seem the same.
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Bluetooth module -- I am using a mobile phone as the controller. You just need to set up a serial port.
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L298N motor controller -- Get a separate battery pack too to run the motors, I have been using 9v (6 AA in series). I have heard they don't cause a big voltage drop like a 9v battery
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The ultra sonic sensor
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And a servo to move the sensor around, I think I got this, not sure anymore. But very similar. Mine had a bracket.
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DX also sell some kits, they're quite cheap too.
And I got some Arduino of Amazon for about 10. It's a good idea too to buy some dupont leads.
So far I have got the car to move around via bluetooth and I have managed to control it's speed. I am just working on the servo and the sensor. I also plan to have some kind of autopilot mode where the car will move around the house by itself just using the sensor as a way not to crash. Let me know if you need help. One major drawback with dx is that you will get no documentation, the internet though has pretty much all you need to know so it may not be a problem.