The amazing thing about the D-Plan was that they sounded so random and odd, but if you listen really closely, everything was actually meticulously arranged and intentional. The out-of-tune guitar sound is actually just really jarring blue chords, for the most part (unless you're listening to a bootleg where the guitars are honestly out of tune).
That and the speaking-no-wait-singing-no-wait-screaming-like-a-maniac style, which is hard to imitate without becoming kind of self-conscious.