Box help and questions for 2 21 inch death penalty subwoofers

[Derek Hathaway]

I have 2 21 inch incriminatoraudio dp subs and 2 2000 watt alpine amplifiers I'm putting them in a 1993 suburban. I have no idea what to do for a box these things are supposed to hit the lows like crazy, but I'm torn between slotted and aero slots. I've never used aero ports but people say great things about them I was told if I walled them not to use aero , but this is a daily driver so I wanted to stay away from a wall anyway. In the past i noticed that slotted seamed somewhat (hollow) when it came to the really lows, someone also said to use both slots and aero ports, I'm not sure how to do that or if it's even possible, the last suggestion was a fourth order box? What is that and would it work with my subwoofers and still rock the lows that there supposed to. With any setup what should i tune them at.Any help would b great I've never worked with subs like these before, thanks guys.