DETROIT, Jan. 7 -- A sprint to 60 miles per hour in less than six seconds, top speed greater than 140 miles per hour, a six-speed manual transmission, rear-wheel drive and an engine displacement of 2.4 liters. These specifications can only mean one thing -- less weight, more fun. Unveiled at the 2002 North merican International Auto Show in Detroit, the Dodge Razor concept car embodies the purest of sports coupe design: aspirational, emotional…