Am I downloading from the wrong site? Is the file safe in another? Has the mod been Compromised? Or is my antivirus giving a false alarm? I'm using McAfee, if that helps you.

Small sugestion, use kaspersky... (It has a free version too)

Else, use this site to be 100% sure https://www.virustotal.com/pt/

(I downloaded my version from there, no problems :D _)

The mod is signed, any tampering with the JAR will cause a signature mismatch - you can use jarsigner to check, I think?