Colin McRae, whose fascination with cars grew into an obsession that led him to 25 wins in a World Rally Championship career, was killed in a helicopter crash along with his 5-year-old son and two others, police said Sunday. He was 39.  McRae was piloting the helicopter, which he owned and was licensed to fly, when it crashed Saturday in a wooded area near his home.  McRae won 25 races in his career in the World Rally series, winning the championship in 1995 before retiring in 2004. He is best known to console and PC gamers for lending his name to a number of highly regarded and best selling rally racing games for developer/publisher Codemasters, including this year's off-road racing game Colin McRae's DiRT.