I so dearly wish he published sheet music for this. I haven't been able to find another transcription of these excerpts that are of comparable quality. Gould for the prelude and Busoni for the Trauermarsch come close, but absolutely nothing for the hair-raising finale
Well, Wagner himself said his music is better than it sounds. I think a piano transcription that is more or less true to the original such as this one is a good example of that statement.