Help on choice driving 2 passive subs?

I am looking for advice on my two choices to drive two NHT SW2 10" ported subs in my theater? (Drive with two channels of a dedicated amp like 200wt Emotiva OR use another subamp(s) with crossover/phase/level control??)
The two SA-2 amps I was using are becoming intermittant so I want to replace them. Does anyone have experience with how important is individual phase control with two subs? How about using one subamp driving both subs in parallel?
Current equipment is: B&K Ref20 preamp, Anthem MCA5, Paradigm Monitor 11's, Reference Center and ADP sourrounds. I also have 4 bass-shakers in seats so the subs don't need to go too low to provide the viceral shake.
My theater is a 15'x25' rectangle with acoustic floating floor and 5" thick full acoustic front wall. The subs can be positioned anywhere from the left side around the front to the right side (not back center).
Thank you for sharing your experience.
(I can share details about how I built my acoustic floor using neoprene and cork pucks if someone is interested.)
I forgot to clarify that my preamp has two sub outs that I would run to either the full range or subamp.