I have regular M80s and they already can go quite low with out the HP upgrade.

All the Axiom line up is tested in the factory with around 3 times the suggested power rating so the 160 should be able to handle the wattage no problem. you may get a little distortion or compression if you maxed out the volume, not likely to damage anything as you'll have plenty of power in reserve.

With the HP you'll either want a huge sub or none at all. I suspect the HP could be set to 40Hz and play all the notes with ease.