 Complete the following phrase:  Attractive as the Monza was, its streamlined body was really only suited to high-speed tracks made up of straights and slow corners, leading to defeat at its second race, the British Grand Prix at the high-speed corner dominated Silverstone circuit, where Fangio hit a number of oil barrels that marked out the circuit. A conventional open-wheel-version was introduced for the most important race on the calendar for Mercedes, the 