The Sat-5 and Magnepan recommendations above sound very good. Magnepans need a lot of power which you do have.
Another option, if you are keeping the Sunfire Sig. Sub, is to get 5 Gallo Acoustics Due's. You can probably make a deal and get them all for $3K. However, this will leave you with no funds left for cables. They are also designed to go on the wall and have a wide dispersion due to their CDT tweeter.
Another option, if you are keeping the Sunfire Sig. Sub, is to get 5 Gallo Acoustics Due's. You can probably make a deal and get them all for $3K. However, this will leave you with no funds left for cables. They are also designed to go on the wall and have a wide dispersion due to their CDT tweeter.