At the very least you will want 2 pumps 4 dumps. As for batteries it depends on what you plan on doing with it, you need at least 24v though, I have 2 Kinetik HC1800's on my accord wagon and I am just raising and lowering and thery seem to be doing just fine.
As for interior modifications...Well that depends on a lot of things. My interior is 99.9% stock, All I have had to do is drill some holes here and there to run some lines. You have an SUV so the rear will need some modification. It really all depends on how the rear suspension gets set up.
Contact Jeremy at Dice Suspension/Tre5 Customs, he has a lot of hydraulic/install experience and good products as well.