In 2006, the regulations were changed drastically – the chassis was replaced and the engines provided by Toyota and Honda had the same specifications as the engines used in the 2005 IndyCar Series.
En 2006, as regulacións cambiaron drasticamente, o chasis foi substituído e os motores provistos por Toyota e Honda tiñan as mesmas especificacións que os motores utilizados na IndyCar Series de 2005.