Winzip (and simular packing programs) is a different type of compression. If you have a file thats originally 1MB and you manage to compress it down to 0.5MB you cannot access the file without having 1MB free RAM or HDD space. It decompress the file(s) first before it access it. This kinda compression is for storage only.
When you compress an audio file to i.e MP3, lets say 4MB, that will be the size it uses to play also. It doesnt decompress the file into 50MB (if that was the source file) before playing it. To be honest i have no idea if its possible to maintain 1:1 quality when converting to another format. I guess it depends on the bitrate. If someone know more about this, then speak
