I have a few questions about the plethora of new Special Abilities introduced in Diamond and Pearl; perhaps someone who's played the Japanese version can answer them.

According to Serebii, the ability "Electric Engine" causes the pokémon's Speed to increase when it is hit with an Electric attack. Is the Speedup instead of, or in addition to, the dealing of damage?

The ability "Filter", possessed by Mr. Mime, apparently causes super-effective attacks to deal half damage. In other words, no attack is super-effective. What about the abilities "Hard Rock" and "Heat Proof"? The former 'lowers the damage' from super-effective attacks; the latter 'lowers the damage' from Fire attacks (and is possessed by a pokémon that would be weak against Fire.) Just how much do these two abilities lower damage? Possibly half, like Filter?