I can't help you with the 804's because I have the 604's. I can tell you that my very picky ears are very satisfied with the B&W 604/Outlaw combo. I have listened to the 804's extensively and to tell you the truth I could not justify the price difference between the 600's. There is no doubt the 804 is better, but, it was in the realm of diminishing returns for me.
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Outlaw 990-7500, OPPO BDP-83, Main L&R: B&W DM604s3, Rears: B&W DM602s3, Ctr: B&W LCR600s3, Velodyne SPL1200R, Outlaw, Signal, Blue Jeans Cables, Sony 52W4100 LCD, Harmony One