The rear shelf spks on my 1998 S70 are shot. <br>They are rattling up a storm. <p>I would like to replace them economically (read - I am too cheap to buy new OEMs which run $260 for the pair). I have the stock head unit SC813. <br>The impedance rating on the rear shelf speakers is 8ohm and I cant find any in the aftermarket that are not 4ohm. <p>Will I burn out my headunit if I drop in a pair of 4 ohm speakers? <br>Any suggestions much appreciated... <p>TIA.