I've owned the Sunfire Cinema Grand 225 by 5 channels amp and magnepan 1.6's front and back and it is really boring definitely not bright or harsh... I would stick with your Outlaw amps as they are a SOLID 4ohm design which is perfect for Magnepans or get some ATI amps or other mosfet amps. The Sunfire gear is not truely differenial balanced in design, and I found no benefit spending more on balanced cables when I had mine.
I would skip the older Theater Grand processors (and almost all older models from other manufactures) because of the lack of HDMI 1.3a switching and newer surround modes (Dolby II rocks!)... if you could wait and maybe upgrade something else I think in 8 months there will be more options for processors that can strip off audio from HDMI (bluray, etc..). Hometheater Processors are like computers..... old technology is not a bargain (Exceptions would be the Proceed, Meridian, Theta, Anthem, and some of the other high end processors that have Dolby II but lack HDMI or or video switching.. These are still superior products.
The good thing about Sunfire gear is you can always sell it pretty easily especially on ebay. My friends older Sunfire receiver the processing chip died and that was an expensive repair, and his Sunfire Cinema Grand was wired wrong (one of the inverting inputs didn't work), and his replacement arrived with a dead channel and had to be opened up to reseat that amplifier board. My Sunfire had dirt in the display brand new from the factory and the lamp died 2 months later. Quality control is just not there when compared to Rotel, Adcom, and other similar priced brands.
But to answer you question between those two I would buy the Outlaw 990 hands down compared to the Sunfire processor, as I considered that before purchasing my Meridian (the new Integra 9.8 (HDMI 1.3a switching, HD audio from HD is built in and would make this an option I would have considered if it had been out) . Resale on the outlaw gear is quite excellent.