If only Axion allows for the same free 30-day trial exactly like Aperion.
Otherwise, I would also stick with Aperion if you are completely happy with it.
Another company that gives you the free 30-day trial including shipping is NHT.
I would get 5 identical NHT Classic Three + the Classic U2 dual subwoofer system.
The U2 Sub system will allow you to use the front Left & Right speaker (Classic Three) in Pure Direct Mode.
Pre-Pro L+R Output connects to the L+R Input of the X1 (active crossover) of the U2 system.
The X1 L+R Hi-Pass Output to the L+R Input of your Amplifier, LFE Output to the A1 (monoblock), which drives the dual subwoofers.
IMO unless tower speakers have built-in subs like the Def Tech BPs or the RBH flagships or the NHT Classic Four (requires additional A1 + X2), you won't get significant bass output anyway.
That's another option: NHT Classic Four for Front L+R, and Classic Three for Center, Surround L+R.
Hey, why don't you do a NHT vs Aperion head-to-head and tell us all about it?