The 990 only display's "7.1" even may have a 5.1 setup but with your setup it will be fine, I have the same thing but with only one sub.

You should definitely see a beg difference when you do the analog hookups well worth it.
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Outlaw 990/7700
SVS 20-39 PC +
SVS MTS-01 towers, MCS-01 center, MBS-01 surrounds
Behringer A500
Samsung PN58A650, DirecTV HR-20 700
Sony CDP-545, Phillips CDR 765
Oppo BDP-93, Panasonic DMR E515
Technics SL-DL5
Squeezebox 3
Remote Harmony One