Complex sentence: During the three years she spent in the United Kingdom, she raced in Formula Ford, Formula Vauxhall, and earned a second-place finish in the Formula Ford Festival at Brands Hatch, the best performance by an American in the event.
Split into simpler sentences: During the three years she spent in the United Kingdom, she raced in Formula Ford and Formula Vauxhall. Nevertheless, she came second in the Formula Ford Festival at Brands Hatch, the best performance by an American in the event.