I've had SAMs and CAMs in my living room at the same time, with and without a sub (JL Audio F112v2), along with some full range speakers (B&W 802d3)
In my room (20x25') with the room placement I had (makes a big difference with the ported SAMs/CAMs), my SAMs comfortably went down to high 40s, and the CAMs to low 50s. For the kind of music I mostly listen to (jazz, vocals, small ensembles), that extra 5-8Hz really made a difference for things like standup bass and some of the lower registers. Absolutely delightful with both the SAMs and the CAMs, but more balanced and full with the SAMs.
When I turned on the sub (tuned to the natural fall off of the Omegas), things got wonderful and rich. For my kind of music, it was mainly resonances that were down in that range, so it really made things richer and more real.
I could get away without a sub with the SAMs, but with the CAMs, even a modest Monoprice 10" THX select sub ($500) that can get you well into the 20s would make a huge difference I think, I would suggest that if you do get a sub, find a fast and clean one. A boomy highly distorted sub would be an absolute shame paired with the wonderful speed and detail of the super alnico's. In the case of the Monoprice THX select subs, they have a 30 day money back policy. Give it a go in your room with your music and see if it is worth the extra $500 (it definitely would be for me)