Grand Theft Auto IV [ Invalid CD Key ]

+1; I also really hate GFWL.

The mod takes away GFWL so that you don't need to activate the game with that key :P

If the retail version of the game (which the OP has obviously already bought) doesn't work, I'm pretty sure that linking to a mod that makes the game usable is fine, even if it can be used to force pirated versions of the game (which have to be supplied by other sources anyways) to "activate".

Don't forget that GFWL is shutting down pretty soon anyways, so the devs themselves will have to replicate the effects of the mod to keep their game functional.