I am looking for a good car to go with my z-5500's. Its going to be used mainly for music and movies (not so much for games). Im debating between the Audigy 4 and X-fi extreme music. They both have DTS decoding, so I was wondering if there is much of a significant performance difference between the two, since the Audigy for is about $70 and the extreme music is $120. Any input would be greatly appreciated. Thanks.