If you have the space, definitely get a pair of subs and consider crossing them higher than the usual 80hz.
The fact your speakers may show decent response down to 80hz or 70hz doesn’t mean it is wise to make them do so.
A great example is the ever popular LS50. You can cross it at 80hz, but by then it is distorting, compressing, and basically unhappy.
150hz is much better.
Ditto the Arias. 6 inch (or whatever) drivers are midrangers, not bass drivers.
A pair of SVS SB1000 will happily stretch to 250hz, and down to 20hz.
Add a MiniDSP, cross them at 150, Eq the room modes and you have great bass for around $1K.
A ‘full range’ model will give you worse bass, no control, and cost thousands.