I just got one and installed it saturday. I'm using it in my wife's car. We got it with the anti theft feature, no stutter. Anti theft is easy to use. I have read that the stutter doesn't work all that well and it wouldn't get much use in her car anyways. On a side note: the open loop idle is really nice. So far, we're happier with the thrasher than any other chips we've had in the car.