Developed exclusively for the US market, the "Race" shoe has wider toe box for added comfort and a sole with extra cushioning and more aggressive design for maximum control working the pedals. The ball of the foot also has an added comfort cell to help reduce shock and vibration.
Driving and racing shoes are usually slightly narrower than athletic shoes. Most drivers like their shoes to fit as snugly as possible to increase pedal feel. If you are between sizes and like your shoes to fit snugly, choose the smaller size. If you are between sizes and have a wide foot or do not like your shoes to fit tight, opt for the larger size.