 Complete the following phrase:  The Duckworth designed GBA V6 was more successful in , its final year of competition. With the Haas team leaving Formula One, the engine would be supplied exclusively to the Benetton team who had used the BMW engine with success in 1986. The restriction of turbo boost to just 4.0 Bar in 1987 helped the Ford engine to be more competitive, although some unreliability had crept in with 9 engine or turbo related retirements during the season. Drivers Thierry Boutsen and Teo Fabi were able to claim one podium finish each during the season, at Austria Fabi and Australia Boutsen, while Boutsen led his first Grand Prix when he briefly led the 