Anything could be in those files so you need to be incredibly careful what you run. Virus scan EVERY SINGLE THING YOU DOWNLOAD.
ZombieModding is literally download the file, run it, it's installed but take my advice. I'm not risking my PC's security to play custom Z's.
I don't touch UGX because they need you to use their installer and I do not want any extra third party programs on my PC just to install mods.
The best part about it, is all these protections come with the free engine so you need not pay a dime. Out engine also comes equip with anti exploit which can stop these at the web browser level before they even get on the machine. This allows us to stop zero days before they infect. It has evolved way beyond typically AVs and doesn't use signatures to catch these baddies, but monitors what they are doing. I'm of course bias to Malwarebytes a little because I work there, but I would also recommend running out main engine. These suckers aren't new forever and can be detected by AVs later on. Another way is to just wait to scan the files for awhile. If nothing happens then you should be good. Use the downloaded file in a sandbox environment or VM and wait for awhile. The best way to protect yourself from these is to be patient with a virtual machine. Zero day malware typically is so new that there is a timer set in place, so you won't know your infected at first (and neither will the staff at the site checking for you after they "verify it".) No AV or site will pick these bad boys up because they are brand new. If you do get infected they aren't going to help you.
It doesn't matter how much a site tells you your safe, or their staff there, take your security matters in your own hands because it is your responsibility. This type gets their name from being zero days since launch, meaning brand new. Zero day malware is what you need to worry about. After downloading said file, run it through your local AV first and then also virus. Traditional malware can be dealt with rather simply. There are 2 types of malware you need to be worried about when downloading things like this: traditional malware and zero day.