 Buzzi then withheld money that had been committed to McLaren to develop the TAG/Porsche turbo engine.This infuriated Dennis and designer John Barnard, who had designed the MP4/2 specifically for the new turbo-charged engine, but now had to re-design his MP4/1 to "E" spec for the TAG engine.The MP4/1E was first driven by Watson, not Lauda, at the Porsche proving ground.