Edgar Prince, an engineer who founded a small tooling firm30 years ago and built it into one of the country's largest suppliers of trim for automotive uses, died March 2 1995 in Holland. Prince, 63, suffered a heart attack at the headquarters of Prince Corp. He was found in an elevator by a company employee and taken to a local hospital where he was pronounced dead. Prince, who held the title of chairman, founded his company in 1965 as a manufacturer of custom tooling for the die casting industry. He branched out into plastic automotive trim in 1972 when Prince Corp. introduced a sun visor with a lighted vanity mirror. The firm experienced rapid growth as it developed into a full-service designer and manufacturer of interior trim. In 1982, Prince Corp. had sales of $30 million. Today, it reports annual sales of more than $500 million and employs 4,500 in the United States, Europe, Japan and Mexico. Prince was active in several philanthropic groups and played a major role in the redevelopment of his native Holland in western Michigan.