Rats!!...well guys, the cat's out of the bag
Yeah, there is a difference.
To be honest though, I didn't notice all that much of a difference other than over-all loudness and more presence, when I crossed the mains at 80hz.
When I noticed the real improvement, was when I started crossing at 60hz and insisted that the towers produce that extra 20 or so more hz of bass.
So yeah,...if the room is not too large, and the speakers are crossed at 80, then the difference isn't all that great.
And in a smaller room with a well integrated sub, the bookshelf system may even be a better bet, as "generally"(in some circles) a bookshelf speaker will outperform a tower pair in the areas of soundstaging and imaging.
YMMV, void where prohibited by law. (in a larger room though.....