More than likely, it's tires. Are you using the same ones as your local "fast guys" or just what came with the car and are they fairly new? Don't expect the same tire life from a buggy as just about any other class will get.

The next most likely thing is your ESC is either not setup correctly to be as smooth as possible or is a lower-end one that is just inherently not that smooth. Buggies run best with ESC's that have the word "smooth" most commonly associated with them such as the LRP or Orion R10.

As well, your diff and/or slipper could both be too tight thereby making your car mimic having bad tires and a cheap ESC.

Finally, it will take some getting used to on behalf of the nut behind the wheel. Your driving inputs will all need to be more precise and more measured compared to other types of cars. You can't just throw it around like you could a 4wd car or a larger truck.