Manual will always be more pure for a sports car, but times sure are changing. With most of the high tech double-clutch technology in new sports cars from Merc, Beemer, Porsche, Ferrari, etc., the "automatic" trannys actually get faster acceleration/lap times than the respective manual transmission variants available. I put quotes on "automatic" because in the case of some like BMW's SMG and M DCT transmission it's not really considered an automatic per se (wiki it, I was confused too initially).