Mike Simcoe, General Motors' vice president of global design, checks out a 1973 Volvo P1800 ES at a car show for GM's design staff last week. Employees brought their own hobby cars to Detroit's famed Woodward Avenue for the annual event. The Volvo was one of a few foreign brand vehicles mixed in with classic Pontiac muscle cars, Chevrolet Corvettes and souped-up hot rods.