I've looked around. Here, on Google, Amazon and no luck.

It seems as though this is a movie-only song and never released on CD so had anyone ever made a clean rip of it?

P.S. This song was also used on Sonny Chiba's Karate Bull Fighter (https://forum.tarantino.info/t/the-hardest-lost-song-shunsuke-kikuchi-champions-of-death-question/2609/2).

Thanks.

EDIT: I've found a lossless copy. No ETA when it'll be released, though. In time.