In advanced road vehicle safety systems it is imperative to have a model describing the vehicle motions and behaviors with sufficient precision. Often a model incorporating a higher level of complexity generates more accurate data, with the disadvantage of demanding additional calculation power. This study will therefore focus on investigating how models of different detail level represents the vehicle behavior, for maneuvers going from moderate to more aggressive. The characteristics in particular investigated are tire saturation, tire force lag and the effect of load transfers. A vehicle testbed has also been developed, making model validations towards experimental data available.