One thing is for sure, you are starting on the right track!! Any of the SEOS designs on DIY soundgroup or the Pi designs will put you well ahead of what you could comparably get with commercial offerings. You will have a theater capable of incredible dynamics. For subs, you could go with one of the Dayton or Stereo Integrity flat packs from DIY soundgroup. Really, you can't go wrong with any of these options. Good luck!