I get pretty good imaging with my towers. Likewise, some say that bass is bloated in a tower. Again, I say that depends on the tower and it's placement in the room.

I prefer to have my main speakers deliver all the sound possible. By using a full range speaker, you have the option of having the sub come into play only in the lowest registers. You won't need it for the mid/upper bass like witt a standmount. Tht improves imaging overall.

I had my sub hooked up to my main (stereo) system and had the speakers running full range from the preamp output with another run going to the sub. I used the sub's low pass filter to have the sub cut in only below 50 hz and I found the sound stupendous. Others were quite impressed as well.

IOW, the sub is very rarely called into play in the stereo and that's the way (uh huh uh huh) I like it.

YMMV