Floyd ain't stopping nobody at 147 or 154 whose chin is better than glass. If you have not enough power to knock down Zab Judah or Andre Berto at 147, you ain't going to stop De la Hoya even if he was 50 y.o.
Zero... I think prime for prime, at 147 I think Oscar would beat Floyd in a close close fight. Oscar would be bigger and most importantly he had one of the best Jabs in boxing history and a hell of a left hook and would be able to match Floyd in the speed department. Great fight!