the simple answer is no.... buy a 2 channel or single channel amp, very cheap one olike 50 or so.... then tune the amplifier to give a lower volume.
if you wire it up to your normal speakers the impeadance will almost certainly blow your head unit, not to mention shuving trebble through a woofer can blow the voice coil, and it would just sound like youve dropped your speakers into a public toilet......
i would deffinatley avoid.