Modding GTA is relatively safe as long as you take some simple precautions. Here they are. For a broader list, see the safe modding checklist.
We do not host downloads - this is intended as educational information. As far as modding in general goes, gtamodding.net is the network's modding hub.
Back up before installing anything
Back up the whole game folder before modding. Restore from the backup if something goes wrong. This tip trumps all others.
Cloud-saved games muddy the waters a bit - some backups don't include cloud saves. Double-check that your backup solution covers what you need.
Source matters
Download mods from reputable hosts. Don't click random Discord links, email attachments you weren't expecting, or 'free' mods from unfamiliar sites. Reputable mod sites have virus scanners and community moderators.
Read comments by users on that particular mod before downloading. If there are dozens of comments warning about the mod, take their word for it.
Isolate online and modded installs
Never take a modded install into online sessions. Keep clean and modded installs separate if you play both.
Update carefully
Mods frequently break or become outdated when Rockstar releases patches. Avoid auto-updating if you have a functioning modded install that you'd like to keep.