There are a couple of small caps on the Mk 2 that affect top end treble on the forward speakers in the car, and the stereo pair at home. By removing them, I have seen/heard a noticeable improvement in sound quality at HF. Also, although impossible to prove, removing them seems to reduce external interference from alternators, especially on BMWs. This is HIGHLY subjective, and impossible to prove by looking at the circuit diagrams, but - I have heard the results! YMMV.