It is not always better to have the subs and ports firing into the cabin. If you face them backwards you get a loading factor, much like putting your home theater sub in a corner. The sound waves really only have one direction to travel, and that's bouncing off of the back of the trunk and into the cabin. If you face the subs forward without sealing off the trunk, you'll have some waves that want to go backwards, back into the trunk, and cause cancellation and things. Your absolute best bet would probably be to face them forward and seal off the trunk behind the front baffle. However this takes some work that some people don't want to do. If you just want a drop-in install that will work just fine, fire both port and subs backwards and rest the box so it's about 6-10" from the back of the trunk. Are you meaning like physically cut a hole into your back seats? I wouldn't do that. People usually have good results cutting extra holes in the back deck though, to allow more sound through. You may have to build both a sealed and ported box to decide which you prefer. Don't worry about using the term SQ.