What's is the best mod?

Hey,

What is the best mod so far? I'm not quite new when it comes to mod a game and I've actually enjoyed installing new mods to GTA San Andreas back in a year.

P.S

I've mentioned GT SA because back then I've collected the best mods for that game tried it with one another to see if it run with/without problem then discard those that crashes it or having conflict with other mods so my question is not only what is the best mod for this game (BGEII) but rather can it also be installed all at once?

Cheers,
BGEFanatic