Your input please: Using sub on 2 channel amp

Yes it is more than possible it,s proven. Just make sure you choose a MUSICAL SUB and not a home theater sub. Rel's are very musical, totem, older NHT's, and others. Cheers

Go with REL. If you use speaker level it will add bass without changing the sound of your main speakers. Will improve the sound even if there is not a lot of bass present.

REL, Velodyne, JL Audio are all excellent choice for musical subwoofers. I have 15 x 20 room with Focal Electra fronts that can go down to 30Hz. The bass response is already pretty good. But when I added DD12 to the system, the bass response went up to the next level. You don't need to listen to bass heavy music. The subwoofer adds nice ambiance to any recording from small band jazz to symphonies.

ML Depth sub along with my 3.6 maggies sound great. Check out the ML line of subs while you are at it.