(Reuters) - General Motors Co unveiled a $288 million data center in the Detroit suburb of Warren on Monday it says will save the company millions of dollars in product development, manufacturing, marketing, and sales. GM has outsourced many of its computing and information technology (IT) functions in recent years, which it says were more costly and not as effective as the two data centers will be for the Detroit-based company. Construction of a $258 million companion data center at the GM vehicle proving grounds in Milford, Michigan, will begin this summer. ...