 Complete the following phrase:  The 1989 season saw a host of regulation changes, the major of which was ending the turbocharger era in Formula One. New naturally aspirated 3.5 litre engines were to be used. Despite Ferrari winning the 1989 Brazilian Grand Prix, McLaren-Honda continued their previous season form. Both Senna and Prost traded wins throughout the season, with the Ferraris on some occasions managing to challenge the powerful Honda V10 McLarens. The first issues began to arise in the McLaren garage at the 