Neither of this is true!
Ghost cars are true, chainsaw men and shit, NOT. If you're new at SA and hear those things like Piggsy, Bigfoot, or something, it's FAKE!
It's something you need from Microsoft to run certain programs. Go to www.microsoft.com and search for .NET Framework; it's 40MB ( ) but it's required.
Well, it actually depends of how you play, but with all the GTA's I've played, I can say that this one is difficult a lot.
Vice City is easy
San Andreas is easy
LCS is very easy
VCS is medium for me.