Is there some way to mod without downgrading?

[Shamiram]

This sounds stupid as hell, and honestly is, but I've tried downgrading my copy and the first time, it was stuck on infinite character loading screen. The 2nd time, it was stuck on copyright screen. I've had the 2nd problem also when using the updated version, which I found out how to fix.
I mean... all I'm gonna do is just change the skins of weapons and give Niko fingerless gloves. Do I really have to downgrade for that?
God Rockstar games is stupid.

[AntiqueGamer]

Short and precise reply: nope! You have to downgrade to mod GTA-IV and that can be a special hell all of its very own. I know it can be frustrating but everytime you mod - even nice mods like those - you break the TOS between you and Rockstar Games. They're not stupid, in fact they were and still are protecting their intellectual property. Actually, be glad of the fact that you can mod at all ... back when I first started out as a gamer (1981) you could not mod a game as the graphics data files were all encrypted. We've come a long way since then.

Didn't stop me breaking the encryption just to see what they looked like.

[B Dawg]

^ Too much unecessary text, and also not true. You don't have to downgrade. And even that is very simple (I prefer the manual downgrade method of extracting files and not relying on installers).
To give Niko fingerless gloves via Simple Native Trainer, just download the Fixed Scripthook.[github.com]
(Only works on IV)
For EFLC, I'd recommend an alternative trainer/menu that doesn't rely on Scripthook, such as Zolika1351's menu.[gtaforums.com]

Changing weapons/textures/replacing models/etc... that was never broken/affected by patches, that's what OpenIV is for and works across all versions.