I'm currently wading throught the posts surrounding "which sub to buy," (for under $1K CAD delivered) and in doing so, began wondering what to do with my (Costco special) David D-Box 300 when I finally pull the trigger on a new sub...maybe keep it and move it to surround-sub duty? My question? Has anyone tried running stereo rca cables from the "surround L & R" pre-outs on the back of the receiver to the L & R ins on a sub? What would happen? If the sub was located behind the prime listening position, with the crossover tweaked, would it add a little punch to the surround channels? I tried searching, and all I could find were instances where people ran the speaker-wire through the sub, then up to surrounds--not the line-level pre-outs. In those posts, there were a number of mentions of cancellation and such, which I understand. Or just sell the d-box for $100 to a friend...Thoughts?