 Complete the following phrase:  During this period, the championship rules were changed frequently by the FIA with the intention of improving the on-track action and cutting costs. Team orders, legal since the championship started during 1950, were banned during 2002, after several incidents, in which teams openly manipulated race results, generating negative publicity, most famously by Ferrari at the 2002 Austrian Grand Prix. Other changes included the qualifying format, the points scoring system, the technical regulations, and rules specifying how long engines and tyres must last. A tyre war between suppliers Michelin and Bridgestone saw lap times fall, although, at the 