If you can take down a badguy boss with out being seen,and that is in 1 of your first missions, you can get some guns and such by doing a silent takedown of the boss, so it would be nice with the stealth option.
Some places list the release date as the 28 and others the first of June.
UK/EU: 28th May
US: 1st June
Its looking to be the same way with crackdown 2 on 360 because the developer is british
As for trainer, the usual, inf ammo, health etc, but a timer freeze would be sweet the computer hacks are hard to see in all those flashing numbers...
As for cheats, it seems to use the Unreal 3 Engine, and so console cheats might work.
I have noticed an entry for console in DefaultInput.ini (in the config folder).
Anyone remembers how to enable console in U3 based games?