I'll also share I had been running my F208's on a Parasound HCA-2200II amp and after the 3rd repair in five years, decided to give the
Hypex 502MP from Audiophonics a go, and it has plenty of power. I do wish I had a 3 channel amp, but my Yammy RX-A3080 seems power the C208 and S206's just fine. I tested center and then the surrounds with the Parasound to see if I could tell a difference and couldn't. It's in storage now. And while I loved the look and feeling with the big old amps, it was nice going from a 66 lb. amp to 17 lbs. I think it's cool how much power the little thing makes.
I'm in a 15x24ft. L shaped room and run two 15" Rythmik FV15HP2 subs for the movies. I don't believe 12-15" sealed subs would get the job done if you listen anywhere near reference levels. I'll listen at about -5dB under and they are working. I had an SVS PB2+(2-12" ported box) for 18 years before these, which I loved, but having the two subs definitely helped FR a bit with my wonky room. Some may cringe when they hear this, but my F208's are crossed over at 100hz to the subs because of how my improved the measurements were in REW.