You will most likely get an answer from someone that deals with the mods from the S-shops, but I'll try to help anyways.
I just checked my tfar and Kidal mods, both are in a 7Z file, I was still able to extract them using WinZip Universal. If i remember correctly, it may not be a free app, but with all the mods that get updated within the unit, I'd say it's worth it. Just right click on the file, choose "open with" and open it with whatever app you use to extract compressed files, it sould still work. Hopefully that helps with that.
Now as far as testing the mods, you can ask someone on teamspeak and they can guide you to a server which may be used, with permission of course, if you want to find out if you've loaded them properly.
Hope I was of use, if not, like I said, someone more experienced should be replying to you soon.
