Re: 2 p210s4 enclosure.
Box size should be fine and tuning is fine but not sure about running without ssf. Don't knowthat much about it all but I use one
Head Unit: Pioneer 800PRS | Tweets: Vifa BC25SC06-04 1" Textile Dome | Mids: Dayton RS180 | Speaker Amp: Infinity Kappa Four | Sub: Dayton HO 15" | Sub Amp: AQ1200D
Legal disclaimer... this is my own personal opinion that I have made from my own personal experience and based on my own personal tastes. At no time have I implied that anyone is wrong in their own opinions and you need to make a decision based on your own opinions.