Mozart would have a hard time wrapping his head around Zeppelin, for reasons having nothing to do with their loudness or wildness. The fact of the recording itself would be a pretty staggering revelation (assuming that Mozart is listening to a Zeppelin record.) Once he got past that, Mozart would have to contend with the idea of electronic instruments, overdubbing, artificial reverb and echo, vari-speed, compression and all the other sonic manipulations at work in a Zeppelin recording. Next, Mozart would be dealing with the music's percussion-centrism, its repetitive structures, and its use of blues tonality and other non-European musical practices. Once he assimilated all of that, there are probably parts he would like and parts he would dislike. He'd probably enjoy the beginning of "Over The Hills And Far Away." I doubt he would enjoy "Black Dog." He'd be fascinated by "Going To California." He'd be horrified by "Kashmir," but the hooks would stick with him. He'd probably find all their vulgarity and innuendo to be delightful, since he himself had an unspeakably filthy sense of humor.