i would highly recommend for you to look into crescendo audio.
theyre a new company but they have excellent customer service and excel in awesome products.
i am currently running 2 crescendo audio 3kwp's.
they do 3,370 watts at 1ohm.
and 4,030 at .5 ohms.
all of those ratings are with extremely low THD percentage.
http://www.crescendoaudio.com/product.php?productid=17515&cat=0&bestseller=Y