I am buying this to accompany my pair of 8030C bought half a year ago for the low end extension.
My room is tiny measuring ~ 2m*3m with a wardrobe making the listening space 1m away from speakers and sub, I opt for the 7040 since it's the only quality sub with highpass filter which fits and don't take up my leg room.
At first I was a bit worried it won't be powerful enough being a 6.5" driver in tiny package, ended up it's a perfect match, with the sensitivity knob matching the Genelec monitors for seamless cross over, and dip switches very easy to make them either having flat bass down to 30hz and hearable at 25hz, or to make it slightly bass elevated by 2db as in preference curve, this is the best purchase decision in my audio journey, now I have almost full 20-20khz sound which is very smooth, can't recommend it more in any space limited rooms