What difference does the difficulty setting make in Saints Row 2?

I have completed Saints Row 2 on normal difficulty, with quite a few activities and diversions still to complete. I am considering switching to Hardcore difficulty, but I would like to have an idea of what the difficulty setting affects.

In particular, I would like to know what sort of effect it has (better enemy AI, enemies do more damage, better accuracy, etc.), and what areas of the game it affects (Story Missions, activities, general gameplay, etc.). Also, are there any bonuses, unlockables, etc., that I can earn by switching to hardcore?

I have the PC version, if that makes any difference.

Solution 1:

Only difference I saw while briefly playing it on Hardcore was that I was taking way more damage when getting hit. Not sure that the AI was any better or more accurate really, just more damage-inducing!