For anyone reporting this mod:
[4.5.2] Original GTA content - Converting these between games is allowed, in moderation. It's a common practice, everyone who has gta installed has access to these vehicles, and getting Rockstar's permission simply won't happen. No point in trying to stop access to something you already have. However, converting excessive amounts of content will detract from interest in scratch-made content. It can also cause issues with Rockstar: if GTAIV's content could be installed into the much cheaper and older San Andreas - GTAIV sales could suffer - and future GTAs will be more likely to contain anti-modding protection. Modding currently encourages people to buy the PC version in order to install mods, which makes us a friend of Rockstar. Let's try to keep it that way.
Weapons aren't a full map. Although I personally dislike such 'new GTA to old GTA' conversions too, I don't think it's against the rules.