The manual is online through outlaw's website.

I would suggest thumbing through that. I own a HTR-5790 (similar to your Yamaha). The 990 probably won't give you any more options you'll actually use BUT, I believe it would sound better.
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Sony HS51 PJ
Outlaw 990 pre/pro
Outlaw 7100 amp
Denon DVD-2910
M&K LCR750
M&K Surround-55 tripole
Dual M&K VX-1250
Outlaw PCAs
Blue Jeans Component and HDMI
Panamax 5500