Is he looking for an SPL set up or daily?
If daily, try 3 15's. The build is easy, you have 49" wide to work with. You can get ~14.5-15.5 uft in there easily under the window and have ~10" to the back hatch. IIRC, 18t x 34d x 49"w. There is plenty of room under the 2nd row seats to mount amps and a batt or 2. Also, i think that year has 2 batt boxes under the hood. I know my 98 Silverado did.
On 2000w, 150+ daily shouldn't be a problem. I think those vehicles peak in the low-mid40hz range.