I have IQ5's and 7's as surrounds and they are laughable in stereo as main units. Not sure the config of the 9's so maybe apples to oranges. The ST's will certainly smoke the 7's w/o even getting off the porch in the process. The 5's and 7's are all I can afford right now. I did try the 7's in my 2 channel rig and that, as I said, was laughable. Really bad overall sound and no bass to speak of. Go ST's.