Is 3.1 acceptable, ie, 2x floor standing+ center +sub, or will that compromise audio performance?.."
Depends on your goal. I plan to use 3.1 for watching TV and movies but I don't care about surround effects. Also, my music listening is 2 channel only so again, no impact. However, if you want surround sound you'll need to add rear speakers.
Is there a way you can get to listen to some of these speakers?
AVR/AMP/Speakers: Marantz AV7005, ATI1803, Salk SongTowers, SongCenter, & Rythmik F12(PEQ) Subwoofer
Source & Accessories: Puget Systems Echo II HTPC, Audio Technica ANC7b, ATH-M50
Office: Puget Systems Traverse 15” Laptop, Alesis M1Active 520 USB, & RBH EP1s
Media Player: JRiver 18