Echo42987 10+ year member
CarAudio.com Veteran
I agree w/ everything this man ever says. He knows what he is talking about!Forget what those other guys said about you needing a new amplifier. There is absolutely nothing at all wrong with the amplifier you intend on using. Great power, good build quality, etc. There is nothing "unclean" about the Kicker amps. The only way switching amplifiers would be beneficial would be if you were increasing power....which in your case is absolutely unnecessary given you already have 300w per side available.
Also, Chuck Music (cmusic) gives the Z6 an outstanding review in this thread about half way down the page;
http://forum.elitecaraudio.com/showthread.php?threadid=133747
If you don't know who he is....he's a multiple time world sound quality champion and is essentially considered to be an authority on the subject. I would trust his opinion/review more than anyone else's on this (or most any other) site. He knows what he is talking about, and knows what music should sound like.
-Nick-