I just meant scan with an Antivirus program before playing the file just in case there is something wrong with it. I have never seen VBR files show bitrate below ~170 before, but that does not mean there are none on the network.

It very much depends on what program and quality the source used to rip the musicfile and whether it's from a CD or an online site.

Downloading a bad file shouldn't mess up anything unless you open it as well. Also you can't scan a file before it's downloaded.