I had a Pioneer Elite receiver in my setup (using as a pre-pro) prior to the Outlaw 990 purchase. It wasn't the 84 (it was a 27), but replacing it with the Outlaw significantly improved the sound in my system. The noise floor is lower with the Outlaw.

I imagine when I finally get around to upgrading my speakers, the improvement will be even more noticable between the two in direct comparison. My existing NHTs aren't nearly as revealing as their replacements will be (Thiel CS2.4s, if all goes well... which means, most likely, an amplifier upgrade soon thereafter ).