You could also try rerecording it through a speakerphone or a walkie talkie? Of course the best way to get that true bootleg feel is to output the whole thing to a VCR and then copy the tape a few more times. Then mess with the tracking a bit when digitizing it again. 😃
I have a bootleg ROTS DVD stashed away somewhere, but I don’t know if the subs are what you’re looking for.