Im upgrading to 1200 watts soon, so ill either be getting a new single fi bl or q or maybe a second ssd. If i get the second ssd, the new box will obviously fill pretty much my whole trunk. I have a ski hatch that allows air to flow freely from the cabin back to the trunk, and my current setup is noticeably louder with the port open (sub back, port back setup). If i build this new box for 2 12s, would it be smarter to leave some room around the edges of the box and leave some room between the back seats/ski port and the box to continue to allow air to flow into the cabin or should i take advantage of every possible inch of trunk space and forget the whole ski port thing? Someone recommended porting it through the ski hatch.... that idea seems like it would just give me alot of port noise....

Whatever set up you decide on you should do whatever you can to get the most air flowing around your box and back into your cabin.